Which of the following is a factor of P(x)?

Correct answer: b 2x − 1

P(1/2) = 1/4 − 3/4 − 11/2 + 6 = 0, so 2x − 1 is a factor.

Why the other options are wrong

• a 2x + 1: P(−1/2) = −1/4 − 3/4 + 11/2 + 6 ≠ 0, so 2x + 1 is not a factor.
• c x + 1: P(−1) = −2 − 3 + 11 + 6 = 12 ≠ 0; it is a different quantity from the one asked for.
• d x − 1: P(1) = 2 − 3 − 11 + 6 = −6 ≠ 0; it is a different quantity from the one asked for.