Answer: x - 12 is not a factor.
Step-by-step explanation:
The equation
x³ - 4x² - 4x + 16
To know which of the following is a factor , we continue to find the value of x and substitute into the equation and see the one that gives zero. The one that gives zero is the factor.
(a) x + 2
If x + 2 = 0
x = -2, now substitute for x in the equation and find out if it will be zero.
x³ - 4x² - 4x + 16 = (-2)³ - 4(-2)² - 4(-2) + 16.
= -8 - 16 + 8 + 16
= 0.
Therefore, x + 2 is a factor.
(b) x - 12
If x - 12 = 0, then x = 12
x³ - 4x² - 4x + 16
(12)³ - 4(12)² - 4(12) + 16
1728 - 576 - 48 + 16
= 1,120 , not a factor.
(c) x - 2
If x - 2 = 0, then x = 2
x³ - 4x² - 4x + 16
(2)³ - 4(2)² - 4(2) + 16
8 - 16 - 8 + 16
= 0, Therefore, x - 2 is a factor.
(d) x - 4
If x - 4 = 0, x = 4
x³ - 4x² - 4x + 16
(4)³ - 4(4)² - 4(4) + 16
48 - 48 - 16 + 16
= 0,therefore, x - 4 is also a factor.
