Question

What’s the explanation

Answer 1

x³ + 2x² - 19x - 20

Explanation:

x + 1 = 0

x = -1

Substitute x = (-1) in the polynomial

x³ + 2x² - 19x - 20 = (-1)³ + 2*(-1)² - 19 *(-1) - 20

= -1 + 2 +19 - 20

= -1 - 20 + 2 + 19

= -21 + 21 = 0

So, (x + 10 ix a factor of x³ + 2x² -19x - 20