Advanced Math practice question

Answer: -1

Divide: x³ − 7x + 6 = (x − 1)(x² + x − 6) = (x − 1)(x + 3)(x − 2). The other roots are −3 and 2, whose sum is −1. (Shortcut: all three roots sum to 0, the negative of the missing x² coefficient, so the other two sum to −1.)

Common wrong answers

If you answered 0

0 is the sum of all three roots, including 1.

If you answered 1

1 has the wrong sign; the quadratic factor is x² + x − 6, whose roots sum to −1.

If you answered -6

−6 is the product of the other two roots.

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