Sample 1
Solve for x in the equation 3(x - 5) = 12.
Solve step by step. First, distribute the 3 across the parentheses: 3(x − 5) = 3x − 15. So 3x − 15 = 12. Add 15 to both sides to keep the equation balanced: 3x = 27. Divide both sides by 3: x = 9. Quick check: 3(9 − 5) = 3 × 4 = 12. Correct. Picture a scale — whatever you do to one side, do exactly the same to the other to keep it level.
Why the other choices are wrong
- A. Probably from forgetting to add the 15 before dividing.
- C. Doesn't satisfy the equation when plugged back in.
- D. Result of an arithmetic slip during the division step.