Question

How many roots does the polynomial function, y = (x + 4)(x-2)(x+7) have?

A. 3
B. 1
C. 2
D. A

Answer 1

A. 3

Explanation:

The polynomial y = (x + 4)(x - 2)(x + 7) has 3 roots.

y = 0 ⇒ (x + 4)(x - 2)(x + 7) = 0 ⇔ x + 4 = 0 ∨ x - 2 = 0 ∨ x + 7 = 0

x + 4 = 0 subtract 4 from both sides

x = -4

x - 2 = 0 add 2 to both sides

x = 2

x + 7 = 0 subtract 7 from both sides

x = -7