What are the real zeros of the function g(x)=x^3+2x^2-x-2

G(-2)  = -8 + 2(-2)^2 -(-2) - 2 
         = -8 + 8 + 2 - 2 = 0

so x = -2 is one zero  and (x + 2) is a factor of  g(x)

use long division to divide g(x) by (x + 2)  we get  x^2 - 1

x^2 -1 = 0  gives x = 1 or -1

So answer is -1, 1 and -2.