Question

Given the polynomial f(x), if (x+5) is a factor, what else must be true?

Answer 1

-5 is the answer, f(-5)= -0, option D for this question.

Answer 2

if (x+5) is a factor,it means (x+5)=0,
if you plug x= - 5 into the main function you must get a zero.
Hence,
f(-5) = 0 must be true.