Advanced Math practice question

Answer: A. 2 and 3

Find two numbers that multiply to +6 and add to −5: they are −2 and −3. So x² − 5x + 6 = (x − 2)(x − 3) = 0, giving x = 2 or x = 3. Check: 4 − 10 + 6 = 0 and 9 − 15 + 6 = 0.

Why the other answers are wrong

B. −2 and −3

The factors are (x − 2)(x − 3), and x − 2 = 0 gives x = +2. The negatives in the factors flip to positives in the solutions.

C. 1 and 6

1 and 6 multiply to 6 but add to 7, not 5. The pair that adds to −5 is −2 and −3.

D. −1 and −6

−1 and −6 add to −7, and substituting either into the equation doesn't give zero: 1 + 5 + 6 = 12.

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