Algebra 1 Workbook — Chapter 8: Systems of Two Linear Equations
SOL A.EI.2 (a, b, c, h) · Companion to Textbook Chapter 8
Each page below is one Canva page. Headings are sized for direct paste: page title as H1, section labels as H2. Figures referenced by filename live in ../figures/. Every numbered item is the same problem as in the textbook, so one answer key serves both. Item numbers run continuously from 1 to 132.
PAGE 1 — Chapter opener
Chapter 8 · Systems of Two Linear Equations
Standard A.EI.2 (a, b, c, h)
In this chapter you will:
- Create a system of two linear equations from a situation, defining variables with units
- Test whether an ordered pair is a solution — it must satisfy both equations
- Solve a system by graphing, by substitution, and by elimination
- Decide whether a system has one solution, no solution, or infinitely many
- Verify a solution algebraically, graphically, and with technology
- Explain your method and interpret the solution in context, with units
Words to know: system of two linear equations · solution of a system · ordered pair · verify · point of intersection · substitution · back-substitute · elimination · addition property of equality · equivalent equation · one solution · no solution · infinitely many solutions · parallel lines · identical lines · break-even point · viewing window · interpret
Convention: a solution of a system is an ordered pair, never a single number. "" is half an answer. Check every candidate in both original equations.
PAGE 2 — What a system is
8.1 A System and Its Solution
FIGURE: fig1-a-system-and-its-solution.png (full width)
Fill in the blanks.
A solution of a system is an ordered pair that makes ____________ equations true.
On a graph, the solution is the point where the two lines ____________________.
Solution of and : ____________
What names it on the graph? _______________________________________
Verify it.
| Equation | Substitute | True? |
|---|---|---|
Is a solution? ______ Show both substitutions:
PAGE 3 — One equation is not enough
Checking Against Both Lines
FIGURE: fig7-checking-a-candidate-point.png (full width)
- Which of and solves and ?
| Point | Solution? | ||
|---|---|---|---|
Explain. Why must an ordered pair satisfy both equations?
PAGE 4 — Building a system from a story
Creating a System
Three steps. ① Define each variable in a ____________ sentence, with ____________. ② Find the two independent ____________. ③ Write one ____________ per fact.
Adult tickets $12, child tickets $8; tickets sold for $408.
Let = _______________________________________
Let = _______________________________________
Tickets: _______________________ Dollars: _______________________
Apply it. coins, nickels and dimes, worth cents.
Let = ____________________ Let = ____________________
Coins: ____________________ Cents: ____________________
Apply it. Rectangle, perimeter cm, length cm more than width.
Let = ____________________ Let = ____________________
Perimeter: ____________________ Relationship: ____________________
Apply it. A class of has more than twice as many boys as girls.
System: ____________________ and ____________________
PAGE 5 — Practice · testing pairs
Practice · Is It a Solution?
- System: and .
| Pair | First equation | Second equation | Solution? |
|---|---|---|---|
| a) | |||
| b) | |||
| c) | |||
| d) |
Verify in and : _______________________________________
Apply it. Ride Rite: $3 plus $2 per mile. Cab Co: $7 plus $1 per mile.
Let = ____________________ Let = ____________________
System: ____________________ and ____________________
Explain. Why can a system of two linear equations never have exactly two solutions?
Find the error. A student says solves and "because ."
What went wrong? _______________________ Correct solution: ____________
Technology. Steps to check in , on a calculator:
Apply it. notebooks and pens cost $13; notebooks and pens cost $23.
Let = ____________________ Let = ____________________
System: ____________________ and ____________________
PAGE 6 — Exit ticket 8.1
Exit Ticket · Lesson 8.1
Name: ________________________ Date: ____________
Is a solution of , ? ______ Show both: ____________
Is a solution of , ? ______ Show both: ____________
fish, twice as many tetras as guppies. System: ____________ and ____________
Explain. What is a solution of a system, and why is it an ordered pair?
PAGE 7 — Solving by graphing
8.2 Solving a System by Graphing
FIGURE: fig6-graphing-a-system.png (full width)
Four steps. ① Solve each equation for ______. ② Graph ______ lines. ③ Read the ____________ point. ④ ____________ in both original equations.
____________________ ____________________
Solution: ____________
Verify in the originals: _______________________________________
From the one-solution figure: solution of , : ____________
Verify: _______________________________________
PAGE 8 — Graphing practice
Practice · Read the Crossing
FIGURE: fig11-blank-grids-systems.png (full page, use Grids A–D)
and Solution: ____________ Verified? ______
and Solution: ____________ Verified? ______
Solve each by graphing.
| System | Solution | Check in both? |
|---|---|---|
| a) , | ||
| b) , | ||
| c) , | ||
| d) , |
- Rewrite, then graph.
| System | Slope-intercept forms | Solution |
|---|---|---|
| a) , | ||
| b) , | ||
| c) , |
and Number of solutions: ____________ Why? ____________
and Number of solutions: ____________ Why? ____________
PAGE 9 — The window that lies
When the Picture Is Incomplete
FIGURE: fig9-window-that-lies.png (full width — do not place text beside it)
Explain. What does the left panel appear to show? Why is that reading wrong?
What did the slopes tell you first? _______________________________________
Technology. Graph and .
Window used: ____________________ Intersection: ____________
Algebraic confirmation: _______________________________________
Explain. When does graphing give an exact answer, and what should you do when it does not?
Find the error. A student graphs and and reports "about ."
What went wrong? _______________________ Correct answer: ____________
PAGE 10 — Systems in a context graph
Reading a Break-Even Point
FIGURE: fig8-context-two-ride-plans.png (half width)
Apply it. Solution: ____________
In a sentence, with units: _______________________________________
Cheaper for miles: ____________ Cheaper for miles: ____________
Apply it. Dana: $60 saved, $5 a week. Eli: $100 saved, $3 a week.
System: ____________________ and ____________________
Window needed: ____________________ Solution: ____________
Apply it. Cost ; revenue .
Solution: ____________ What it means: _______________________________________
Graph and . Solution: ____________
Why can not be written as ? _______________________________________
PAGE 11 — Exit ticket 8.2
Exit Ticket · Lesson 8.2
Name: ________________________ Date: ____________
, Solution: ____________ Verified? ______
, Solution: ____________ Verified? ______
Two lines both fall units per unit right and cross the -axis at different points.
Number of solutions: ____________ Why? _______________________________________
Technology. No crossing on the standard window, but the slopes differ. Conclusion and next step:
PAGE 12 — Substitution
8.3 Solving by Substitution
Five steps. ① ____________ one variable in one equation. ② Substitute into the ____________ equation. ③ Solve the ____________-variable equation. ④ ____________-substitute. ⑤ Write the ____________ pair and verify.
,
Substituted equation: _______________________ ______ ______ Pair: ____________
, Pair: ____________
, Set equal: _______________________ Pair: ____________
, Isolated: ____________________ Pair: ____________
Verify item 45.
| Equation | Substitute | True? |
|---|---|---|
Explain. Why is substitution easiest when a variable has coefficient or ?
PAGE 13 — Substitution practice
Practice · Substitute and Solve
- A variable is already isolated.
| System | Substituted equation | Solution |
|---|---|---|
| a) , | ||
| b) , | ||
| c) , | ||
| d) , |
- Isolate first. Say which variable you chose and why.
| System | Variable isolated | Solution |
|---|---|---|
| a) , | ||
| b) , | ||
| c) , |
, Statement you end with: ____________
Solutions: ____________________ Picture: ____________________
, Statement you end with: ____________
Solutions: ____________________ Picture: ____________________
PAGE 14 — Substitution in context
Apply It · Substitution
Apply it. Two numbers: sum , difference .
System: ____________________ and ____________________ Numbers: ______ and ______
Apply it. Solve your item 11 rectangle. Width: ______ cm Length: ______ cm
Apply it. Solve your item 12 class. Boys: ______ Girls: ______
Apply it. Plan A: $25 plus $0.10 per minute. Plan B: $15 plus $0.15 per minute.
System: ____________________ and ____________________ Solution: ____________
In a sentence, with units: _______________________________________
Explain. Name a system where substitution is clearly better, and one where it is painful.
Find the error. A student substitutes back into that same equation and gets .
What went wrong? _______________________________________________
Correct work with : _______________________ Solutions: ____________
, Solution: ____________ Graphical confirmation: ____________
PAGE 15 — Exit ticket 8.3
Exit Ticket · Lesson 8.3
Name: ________________________ Date: ____________
, Solution: ____________
, Solution: ____________
, Isolated: ____________ Solution: ____________
Apply it. Solve your item 19 fish tank. Guppies: ______ Tetras: ______
PAGE 16 — Elimination
8.4 Solving by Elimination
Five steps. ① Line up ____________ terms. ② Make one pair of coefficients ____________. ③ ____________ the equations. ④ Solve for the surviving variable. ⑤ Back-substitute, write the pair, and ____________.
, Sum: ____________ Solution: ____________
, Sum: ____________ Solution: ____________
, Multiplied ______ by ______ Solution: ____________
, Multipliers: ______ and ______ Solution: ____________
Verify item 66.
| Equation | Substitute | True? |
|---|---|---|
Explain. Why does adding the two equations give a true equation? Name the property.
PAGE 17 — Elimination practice
Practice · Eliminate a Variable
- Add or subtract as they stand.
| System | Variable eliminated | Solution |
|---|---|---|
| a) , | ||
| b) , | ||
| c) , | ||
| d) , |
- Multiply one equation first.
| System | Multiplier | Solution |
|---|---|---|
| a) , | ||
| b) , | ||
| c) , |
- Multiply both equations.
| System | Multipliers | Solution |
|---|---|---|
| a) , | ||
| b) , |
, Ends with: ____________ Solutions: ____________ Graph: ____________
, Ends with: ____________ Solutions: ____________ Graph: ____________
PAGE 18 — Elimination in context
Apply It · Elimination
FIGURE: fig10-context-tickets-system.png (half width)
Apply it. Solve your item 16 notebooks and pens. Notebook: $______ Pen: $______
Apply it. Solve your item 5 theater. Adult: ______ Child: ______
Apply it. Solve your item 9 coins. Nickels: ______ Dimes: ______
Apply it. tickets, $50 taken in, adult $5 and student $3.
System: ____________________ and ____________________ Solution: ____________
Does it match the marked point on the figure? ______
Explain. Why does multiplying one equation by a nonzero number leave the solution set unchanged? What goes wrong at ?
Find the error. Subtracting from , a student writes .
What went wrong? _______________________ Solution: ____________
PAGE 19 — Exit ticket 8.4
Exit Ticket · Lesson 8.4
Name: ________________________ Date: ____________
, Solution: ____________
, Solution: ____________
, Multiplier: ______ Solution: ____________
Apply it. Five hot dogs and two drinks cost $17; three hot dogs and four drinks cost $20.
System: ____________________ and ____________________
Hot dog: $______ Drink: $______
PAGE 20 — The three cases
8.5 One, None, or Infinitely Many
FIGURE: fig5-three-cases-side-by-side.png (full width — do not place text beside it)
Complete the table.
| Case | Slopes | -intercepts | Algebra ends with | Solutions |
|---|---|---|---|---|
| Intersecting | ||||
| Parallel | ||||
| Identical |
- Name the three cases shown, left to right: ____________, ____________, ____________
PAGE 21 — Each case up close
One, None, Infinitely Many
FIGURE: fig2-system-one-solution-intersecting.png (one-third width)
- Classify, and justify with the slopes: _______________________________________
FIGURE: fig3-system-no-solution-parallel.png (one-third width)
- Classify, and justify with slopes and intercepts: _______________________________________
FIGURE: fig4-infinitely-many-same-line.png (one-third width)
Classify, and show that one equation is a multiple of the other:
, Classification: ____________________ How you decided: ____________
, Classification: ____________________ How you decided: ____________
PAGE 22 — Classification practice
Practice · Count the Solutions
- Compare slopes and intercepts.
| System | Slopes | Intercepts | Solutions |
|---|---|---|---|
| a) , | |||
| b) , | |||
| c) , | |||
| d) , | |||
| e) , |
- Rewrite in slope-intercept form, then classify.
| System | Rewritten | Solutions |
|---|---|---|
| a) , | ||
| b) , | ||
| c) , |
, has no solution when ______
Why can no give infinitely many? _______________________________________
, has infinitely many when ______
Every other gives ____________________ because _______________________
PAGE 23 — Classification in context and errors
Apply It · What the Count Means
Apply it. Shop A: $45 plus $3 per shirt. Shop B: $60 plus $3 per shirt.
System: ____________________ and ____________________ Classification: ____________
What it means for a customer: _______________________________________
Explain. Why can a system of two linear equations never have exactly three solutions?
Find the error. A student reaches and writes "no solution."
What went wrong? _______________________ Correct conclusion: ____________________
Explain. Connect "the variables vanished and left a false statement" to "the lines are parallel."
PAGE 24 — Exit ticket 8.5
Exit Ticket · Lesson 8.5
Name: ________________________ Date: ____________
, Solutions: ____________ Graph: ____________________
, Solutions: ____________ Graph: ____________________
, Solutions: ____________ If one, find it: ____________
Explain. The difference between ending with and ending with :
PAGE 25 — The five-step model
8.6 Modeling with Systems
FIGURE: fig10-context-tickets-system.png (half width)
Five steps. ① Define both variables in full ____________, with ____________. ② One equation per independent ____________. ③ ____________, and say why you chose that method. ④ Verify ____________ ways. ⑤ ____________ the pair as a sentence.
Apply it. Adult tickets $5, student tickets $3; tickets, $50.
Let = _______________________ Let = _______________________
System: ____________________ and ____________________ Solution: ____________
Sentence: _______________________________________
Apply it. Use the ride-plan figure. Variables, system, solution, and what each side of the crossing means:
PAGE 26 — Verifying three ways
Three Kinds of Evidence
marbles, more blue than red. System: ____________ and ____________ Solution: ____________
Verify item 104 three ways.
| Check | What you do | What you find |
|---|---|---|
| Algebraically | ||
| Graphically | ||
| With technology |
Explain your method. Name the method, the reason, the key step, and the check.
vehicles — vans hold , buses hold — carry people.
System: ____________________ and ____________________ Solution: ____________
Why it cannot describe the trip: _______________________________________
PAGE 27 — Modeling practice
Apply It · Build, Solve, Interpret
Apply it. Gym A: $50 to join, $20 a month. Gym B: $20 to join, $25 a month.
System: ____________ and ____________ Solution: ____________ Sentence: ____________
Apply it. Garden perimeter ft, length three times the width.
System: ____________ and ____________ Length: ______ ft Width: ______ ft
Apply it. bills, twos and fives, worth $70.
System: ____________ and ____________ Twos: ______ Fives: ______
Apply it. A -cm candle burns cm per hour; a -cm candle burns cm per hour.
System: ____________ and ____________ Solution: ____________
Sentence: _______________________________________
Technology. Check item 111. Window: ____________ Reported point: ____________ Agrees? ______
PAGE 28 — Reasoning and errors
Explain and Correct
Explain. Why does substituting into only one equation prove nothing?
Find the error. A student finds and writes "the solution is ."
What is missing? _______________________________________________
A complete answer looks like: _______________________________________
Apply it. Shop A: $45 plus $3 per shirt. Shop B: $60 plus $3 per shirt.
Solution: ____________________ What it means for a customer: ____________________
Apply it. " lb trail mix and lb nuts for $14" and " lb trail mix and lb nuts for $28."
System: ____________ and ____________ Classification: ____________________
Why the second ad adds nothing: _______________________________________
PAGE 29 — Exit ticket 8.6
Exit Ticket · Lesson 8.6
Name: ________________________ Date: ____________
Apply it. questions worth or points each, points total.
Let = _______________________ Let = _______________________
System: ____________ and ____________ Solution: ____________
Verify algebraically in both, and describe the graphical check:
Interpret in one sentence with units: _______________________________________
Technology. How you would confirm it, and what a different reported point would mean:
PAGE 30 — Chapter 8 review · creating and solving
Chapter 8 Review
Part A · Creating a system from a context
Apply it. Pencils $0.50, erasers $0.75; items sold for $25.
Let = ____________________ Let = ____________________
System: ____________ and ____________ Solution: ____________
Apply it. Sum ; the larger is less than twice the smaller.
System: ____________ and ____________ Numbers: ______ and ______
Part B · Solving algebraically and graphically
, by graphing Solution: ____________ Verified? ______
, by substitution Solution: ____________
, by elimination Solution: ____________
, by any method Method: ____________ Why: ____________ Solution: ____________
PAGE 31 — Chapter 8 review · counting, verifying, interpreting
Chapter 8 Review (continued)
Part C · Counting the solutions
FIGURE: fig5-three-cases-side-by-side.png (full width)
, Solutions: ____________ Graph: ____________________
, Solutions: ____________ Graph: ____________________
, Solutions: ____________ If one, find it: ____________
Part D · Verifying, explaining, interpreting
- Verify your item 126 answer three ways.
| Check | What you do | What you find |
|---|---|---|
| Algebraically | ||
| Graphically | ||
| With technology |
Apply it. Tank A: L draining L per minute. Tank B: L filling L per minute.
System: ____________ and ____________ Solution: ____________
Sentence: _______________________________________
Explain. Method, reason, key step, three-way verification, and whether the answer is reasonable:
PAGE 32 — Blank grids
Graph Paper
FIGURE: fig11-blank-grids-systems.png (full page)
Use these grids for any system a teacher assigns alongside this chapter: graphing two lines to find where they cross, checking an algebraic answer against a picture, or drawing the parallel pair that shows why a system has no solution.
Three reminders for every sketch:
- Solve each equation for before graphing, then plot from the -intercept using the slope.
- Mark the crossing point and label it as an ordered pair, not as a single number.
- A reading off a grid is a claim. Finish by substituting the pair into both original equations.
Canva production notes
- Page size: 8.5 × 11 in, 0.75 in margins
- Type: headings 24–28 pt, body 12–14 pt, answer blanks 14 pt with 1.5 line spacing
- Item order: a few items are placed by figure rather than by number, so that every item on a page can be answered from the figure on that page. Page 3 runs 4 then 6; page 4 runs 5, 9, 11, 12; page 5 runs 7, 8, 10, 13–16; page 9 places 26 before 33–35; page 21 runs 85–89 beside the three case figures. The numbers still match the textbook exactly, and the answer key is in numerical order.
- Figure widths:
fig1-a-system-and-its-solution.png,fig6-graphing-a-system.png, andfig7-checking-a-candidate-point.pngare full width on first appearance.fig5-three-cases-side-by-side.pngandfig9-window-that-lies.pngare wide multi-panel images — set them full width and do not place text beside them, or the panels shrink below readable. On page 21 the three single-case figures sit in a row at one-third width each; if that crowds the labels, stack them and let the page run to two columns instead.fig10-context-tickets-system.pngrepeats on pages 18 and 25, andfig5repeats on page 31; repeat the image rather than asking students to flip back.fig11-blank-grids-systems.pngtakes a full page on its own and is also referenced from page 8. - The graphing pages need real grids. Items 24, 25, 27, 28, 29, 30, and 37 are all solve by graphing, and there is no room to draw two lines in a text blank. Place the four grids of
fig11-blank-grids-systems.pngon page 8 and label which grid goes with which item, or add a second copy of that page. - Blank work space: items 6, 13, 20, 26, 34, 40, 41, 47, 56, 57, 68, 78, 92, 93, 95, 96, 97, 101, 106, 113, 114, 116, 120, and 132 are written explanations — give each at least four ruled lines, not a single blank. Item 132 asks for five separate things and needs eight lines.
- Ordered pairs versus single numbers: every blank labeled "Solution" must be wide enough for an ordered pair with parentheses and a comma, and should be pre-printed with the parentheses —
(______ , ______)— because reporting a single number is this chapter's most common error and the blank itself can prevent it. - Verification tables appear on pages 2, 3, 12, 16, 26, and 31. Keep all three rows of the three-way tables on one page; splitting "with technology" onto the next page is what makes students skip it.
- Fractions: items 25, 27d, 86, 90b, 91, 93, and 127 have fractional slopes. Set them as stacked fractions, not slashes, so that never reads ambiguously across a line break.
- Negative signs: use the typographic minus (−), matching the figures, not a hyphen.
- Currency: dollar amounts appear on pages 4, 5, 10, 14, 18, 19, 23, 27, 28, and 30. Set them as plain text ($12, $8, $408, $3, $2, $7, $13, $23, $25, $15, $17, $20, $45, $60, $50, $70, $14, $28, $0.50, $0.75), not inside a math box.