Worked example
Solve: 5x + 3 = 2x + 15. What is x?
Answer & why
Answer: 4
Subtract 2x and 3 from both sides: 3x = 12. Divide by 3, so x = 4.
Grade 8 · Math
Solve equations with variables on both sides
Use equivalent transformations to solve a linear equation with variables on both sides.
6 authored questions + worked example
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All questions
All 6 authored questions for this skill.
Question 1
Solve: 6x + 5 = 2x + 25. What is x?
- 6
- 5
- 4
- 7
A hint
Move variable terms to one side and constants to the other using the same operation on both sides.
Answer & why
Answer: 5
Subtract 2x and 5 from both sides: 4x = 20. Divide by 4, so x = 5.
Question 2
Solve: 8x + 4 = 3x + 14. What is x?
- 4
- 2
- 3
- 1
A hint
Move variable terms to one side and constants to the other using the same operation on both sides.
Answer & why
Answer: 2
Subtract 3x and 4 from both sides: 5x = 10. Divide by 5, so x = 2.
Question 3
Solve: 9x + 1 = 5x + 25. What is x?
- 5
- 6
- 8
- 7
A hint
Move variable terms to one side and constants to the other using the same operation on both sides.
Answer & why
Answer: 6
Subtract 5x and 1 from both sides: 4x = 24. Divide by 4, so x = 6.
Question 4
Solve: 4x + 7 = 1x + 31. What is x?
- 10
- 8
- 9
- 7
A hint
Move variable terms to one side and constants to the other using the same operation on both sides.
Answer & why
Answer: 8
Subtract 1x and 7 from both sides: 3x = 24. Divide by 3, so x = 8.
Question 5
Solve: 5x + 3 = 2x + 15. What is x?
- 6
- 4
- 3
- 5
A hint
Move variable terms to one side and constants to the other using the same operation on both sides.
Answer & why
Answer: 4
Subtract 2x and 3 from both sides: 3x = 12. Divide by 3, so x = 4.
Question 6
Solve: 7x + 2 = 4x + 11. What is x?
- 5
- 2
- 4
- 3
A hint
Move variable terms to one side and constants to the other using the same operation on both sides.
Answer & why
Answer: 3
Subtract 4x and 2 from both sides: 3x = 9. Divide by 3, so x = 3.