Advanced MathHardSum of the solutions of a quadratic
Advanced Math practice question
What is the sum of all solutions to the equation x² + x − 6 = 0?
Answer: -1 or −1
Factor: (x + 3)(x − 2) = 0, solutions −3 and 2; their sum is −1. (For any x² + bx + c = 0, the solutions sum to −b.)
Common wrong answers
- If you answered 1
- 1 has the wrong sign; the sum of the roots is −b = −1.
- If you answered 5
- 5 adds the absolute values of the roots.
- If you answered -6
- −6 is the PRODUCT of the roots (−3 × 2), not their sum.
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