Algebra practice question

Answer: 12

Let the number be x: 2x − 7 = x + 5. Subtract x: x − 7 = 5, so x = 12. Check: 24 − 7 = 17 and 12 + 5 = 17.

Common wrong answers

If you answered 2

2 is 12/6 or (7 − 5); the equation gives x = 12.

If you answered 4

4 comes from 3x = 12 (adding x instead of subtracting it).

If you answered -2

−2 comes from 2x − 7 = x + 5 solved as x = 5 − 7; the 7 moves across as +7: x = 5 + 7.

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