Question

What are the zeros of the polynomial function?

f(x) = x^3 + 2x^2 - x - 2

select each correct answer:
-3
-2
-1
0
1
2
3

Answer 1

-2, -1 and 1.

Explanation:

x^3 + 2x^2 - x - 2 = 0

x^2(x + 2) - 1(x + 2) = 0 Note the common factors (x + 2) so we have

(x^2 - 1)(x + 2) = 0

(x - 1)(x + 1)(x + 2) = 0 (x^2 -1 is the difference of 2 squares).

x = -2, -1 and 1.