Algebra practice question

Answer: 4

Dividing by 2: x − c > 5, so x > c + 5. Matching x > 9 gives c + 5 = 9, so c = 4.

Common wrong answers

If you answered 5

5 is the bound on x − c after dividing by 2; c itself is 9 − 5 = 4.

If you answered 9

9 is the boundary of the solution set; c sits 5 below it.

If you answered 14

14 adds instead of matching: the boundary satisfies c + 5 = 9.

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