Answer:
The zeros occur when x = -3 , -1 , 1 and 7
Step-by-step explanation:
I don't exactly know how to do this so I can show you how to do it using some sort of method of division. There are 2 huge steps to be taken. Start with 1
Using synthetic division you get
-1 || 1 - 4 -22 4 21
-1 5 17 -21
===================
1 - 5 -17 21 0
So far we have x = - 1 or (x + 1) is a factor.
It turns out by trial and error that x = - 3 is a factor. What you get after that synthetic division is x^2 - 8x + 7 which factors into (x - 7)(x - 1)
So what we get is
(x - 1)(x + 1)(x - 7 )(x +3)
