Question

Erik used the Factor Theorem to find the remainder of 2x3-4x2-28x+6 divided by x+3. If he calculated the remainder to be 0, what does that tell him?

Answer 1

Explanation:

x + 3 = 0

x = - 3

f(x) = 2x³ - 4x² - 28x + 6

f(- 3) = 2(- 3)³ - 4(- 3)² - 28 x (- 3) + 6

= 2 x (- 27) - (4 x 9) + 84 + 6

= - 54 - 36 + 90

= - 90 + 90

= 0

Therefore,

x + 3 is factor of 2x³ - 4x² - 28x + 6