Question

Why is it that when (x+1) is a factor that a root (of the same polynomial) is NEGATIVE one? I don't get that!

Answer 1

you are looking for the value of x that makes the factor or polynomial equal to zero

so you need to solve

x + 1 = 0 which gives x = -1 as the zero

in a polynomial where (x + 1) such as

(x+1)(x^2 +3x + 8)

is you substitute x = -1 then the factor (x + 1) will be zero

and zero times any number is zero.

hope this helps and makes some sense..

Answer 2

Yes, it did, thanks! Math books are notorious for leaving off a bit that might make all the difference! =)