Question 11
PolynomialsIf x − 1 and x + 1 are both factors of the equation x3 + px2 + qx + 6 = 0, evaluate p and q.
- A.−6, −1
- B.6, 1
- C.1, −1
- D.6, −6
Show the answer and explanation
Answer: A (−6, −1)
Explanation
x = 1 gives 1 + p + q + 6 = 0, so p + q = −7. x = −1 gives −1 + p − q + 6 = 0, so p − q = −5. Adding: 2p = −12, p = −6 and q = −1.