Answer:
Step-by-step explanation:
The easiest way to do this is by using synthetic division (I really hope you know what I'm talking about!)
If the factor is x + 2 = 0, then the solution or the root is x = -2. We will put -2 outside the "box" and the coefficients from the terms of the polynomial inside the "box":
-2| 1 0 0 8
Bring down the first number and multiply it by the -2. Put the product up under the first 0 and add:
-2| 1 0 0 8
-2
1 -2
Now multiply the -2 by the -2, put the product up under the next 0 and add:
-2| 1 0 0 8
-2 4
1 -2 4
Now multiply the 4 by the -2, put the product up under the 8 and add:
-2| 1 0 0 8
-2 4 -8
1 -2 4 0
Those bold numbers are the coefficients to the quotient, which is another polynomial, but is one degree less than the one you started with:
x² - 2x + 4 = 0
Since there is no remainder, then x = -2 is a zero of x³ + 8, and (x + 2) is a factor.
There is a whole world of stuff to learn about quadratics!!
