Question

use the factor theorem to factorise x3+x2-4x-4 ...
Answer is (x+1) (x+2) (x-2) but I need way. (Prossager)

Answer 1

Put x=-1 in given polynomial and the remainder will be zero, So we can also write as x = - 1 as x+1: So x+1 is the first factor
Now Divide the polynomial by x+1 and the quotient will be x2 - 4, then factorise this by identity x2 - y2,
x2 - 4= (x)square - (2)square =(x+2) (x-2)
So all factors is (x+1) (x+2)(x-2)

Answer 2

Answer:

x^3 + x^2 -4x -4

Suposse ,let's take x= -1

(-1)^3 + (-1)^2 -4 (-1) -4

= -1 +1 +4 -4

=0