Algebra practice question

Answer: C. 18

Add 5 to both sides: (2/3)x = 12. Multiply both sides by 3/2: x = 18. Check: (2/3)(18) − 5 = 12 − 5 = 7. ✓ (A) 3 comes from subtracting 5 instead of adding it, giving (2/3)x = 2 and x = 3. (B) 8 comes from multiplying 12 by 2/3 instead of dividing by 2/3. (D) 36 comes from multiplying by 3 but forgetting to divide by 2.

Why the other answers are wrong

A. 3

You subtracted 5 from both sides instead of adding, getting (2/3)x = 2; adding 5 gives (2/3)x = 12 and x = 18.

B. 8

You multiplied 12 by 2/3 instead of dividing by it — to undo multiplication by 2/3, multiply by 3/2, giving 18.

D. 36

You multiplied 12 by 3 but forgot to divide by 2; the full step is 12 · (3/2) = 18.

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