Advanced Math practice question

Answer: 5

Factor: (x − 5)(x + 2) = 0, so x = 5 or x = −2. The positive one is 5. Check: 25 − 15 − 10 = 0.

Common wrong answers

If you answered 2

2 has the wrong sign; x + 2 = 0 gives x = −2.

If you answered 10

10 is the constant term; x = 10 gives 100 − 30 − 10 = 60.

If you answered -2

−2 is the other solution, which is negative.

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