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Linear Equations Worksheet Answer Key – Algebra 1

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Last updated: October 22, 2026 · Written by the Math Made Easy math teachers

Algebra 1 Math Worksheet Answer Keys – Mathbot, the Math Made Easy robot coach, with free printable worksheet answer keys for Algebra 1

Looking for a linear equations worksheet answer key? Then this answer key gives every step of the Algebra 1 worksheet on Solving Linear Equations and Rearranging Formulas. Each answer key shows every algebra step and a substitution check. When a step is justified by a property, the name of the property is given so you can compare it with your own reasoning.

Standards: A-REI.A.1, A-REI.B.3, A-CED.A.1, A-CED.A.4 · Level: Grade 9 Algebra 1

Problem 2 Distribute and solve

Divide both sides by 5: x − 3 = 7. Add 3: x = 10.

Check: 5(10 − 3) = 35.

x = 10

Problem 3 A fraction on the variable

Subtract 3: x4 = 5. Multiply by 4: x = 20.

Check: 20/4 + 3 = 8.

x = 20

Problem 4 Negative coefficient

Subtract 9: −2x = −16. Divide by −2: x = 8.

Check: 9 − 16 = −7.

x = 8

Problem 5 Justify each step

Add 7 to both sides: 4x = 28. Divide both sides by 4: x = 7.

4x − 7 = 21 given4x = 28 addition property of equality (add 7)x = 7 division property of equality (divide by 4)
Reasons filled in.

Check: 4(7) − 7 = 21.

x = 7

Problem 6 Variables on both sides

Subtract 2x: 3x − 8 = 19. Add 8: 3x = 27. Divide: x = 9.

Check: 5(9) − 8 = 37 and 2(9) + 19 = 37.

x = 9

Problem 7 Distribute on the left

Distribute: 6x − 3 = 4x + 9. Subtract 4x: 2x − 3 = 9. Add 3: 2x = 12, so x = 6.

Check: 3(11) = 33 and 4(6) + 9 = 33.

x = 6

Problem 8 Fraction coefficient

Add 4: (5/6)x = 25. Multiply by 6/5: x = 30.

Check: (5/6)(30) − 4 = 25 − 4 = 21.

x = 30

Problem 9 Fractions on both sides

Multiply both sides by 4: x + 5 = 2(x − 1) = 2x − 2. Subtract x: 5 = x − 2, so x = 7.

Check: 12/4 = 3 and 6/2 = 3.

x = 7

Problem 10 Decimal equation

Multiply by 100: 40x + 150 = 15x + 400. Subtract 15x and 150: 25x = 250, so x = 10.

Check: 4 + 1.5 = 5.5 and 1.5 + 4 = 5.5.

x = 10

Problem 11 No solution

Distribute: 4x + 8 = 4x + 5. Subtract 4x: 8 = 5, which is false.

The graph shows parallel lines, so they never meet.

xy−4−3−2−1123−448121620
Left side y = 4(x + 2) in blue, right side y = 4x + 5 in orange.

No solution

Problem 12 Every number works

Distribute: 10x + 15 = 10x + 15. Both sides are identical, so the statement is always true.

Infinitely many solutions (all real numbers)

Problem 13 Find the error

The 5 must multiply both terms: 5(x − 2) = 5x − 10.

Then 5x − 10 = 3x + 6, so 2x = 16 and x = 8.

Check: 5(6) = 30 and 3(8) + 6 = 30.

x = 8

Problem 14 Triangle area formula

Multiply both sides by 2: 2A = bh. Divide both sides by b.

h = 2Ab

Problem 15 Comparing gym plans

Let m be months: 25 + 12m = 40 + 9m. Subtract 9m: 25 + 3m = 40. Subtract 25: 3m = 15, so m = 5.

Check: 25 + 60 = 85 and 40 + 45 = 85.

5 months

Problem 16 Taxi fare

3.50 + 2.25m = 21.50. Subtract 3.50: 2.25m = 18. Divide: m = 8.

Check: 3.50 + 18 = 21.50.

8 miles

Problem 17 Temperature formula

Subtract 32: F − 32 = (9/5)C. Multiply by 5/9: C = (5/9)(F − 32).

For F = 95: C = (5/9)(63) = 35.

C = (5/9)(F − 32); C = 35 when F = 95

Problem 18 Perimeter of a triangle

x + (2x + 3) + (3x − 1) = 62, so 6x + 2 = 62 and 6x = 60, giving x = 10.

Sides: 10, 23 and 29.

102329
Sides 10, 23 and 29 add to 62.

Check: 10 + 23 + 29 = 62.

x = 10; sides 10, 23, 29 inches

Problem 19 Missing base of a trapezoid

Multiply by 2 and divide by h: b₁ + b₂ = 2A/h, so b₂ = 2A/h − b₁.

Values: 2(84)/7 − 9 = 24 − 9 = 15.

A = ½h(b₁ + b₂)2A ÷ h = b₁ + b₂168 ÷ 7 = 24 = 9 + b₂b₂ = 15
Steps for the missing base.

b₂ = 2A/h − b₁ = 15 feet

Problem 20 Robotics fundraiser

245 + 35k = 1,260. Subtract 245: 35k = 1,015. Divide by 35: k = 29.

Check: 35(29) = 1,015 and 1,015 + 245 = 1,260.

29 kits