Is x+1 a factor of x3+8x2+11x−20? Precalculus Real Zeros of Polynomials Remainder and Factor Theorems 1 Answer Cesareo R. Nov 8, 2016 (x+1) is not a factor, but (x−1) is. Explanation: Given p(x)=x3+8x2+11x−20 if x+1 is a factor of p(x) then p(x)=(x+1)q(x) so for x=−1 we must have p(−1)=0 Verifying on p(x) p(−1)=(−1)3+8(−1)2+11(−1)−20=−24 so (x+1) is not a factor of p(x) but (x−1) is a factor because p(1)=1+8+11−20=0 Answer link Related questions What is the remainder theorem? What is the factor theorem? What does the remainder theorem mean? What does the factor theorem mean? How are the remainder and factor theorems useful? How do I use the remainder theorem to evaluate polynomials? How do I use the remainder theorem to divide 2x2−5x−1 by x−3? How do I use the remainder theorem to divide 2x2−5x−1 by x−4? How do I use the factor theorem to prove x−2 must be a factor of 2x3−x2−7x+2? How do I use the factor theorem to prove x−4 must be a factor of x2−3x−4? See all questions in Remainder and Factor Theorems Impact of this question 2797 views around the world You can reuse this answer Creative Commons License