Which expression is equivalent to 7a4 - 28?

a) -7(a2 + 2)(a2 + 2)

b) 7(a2 + 2)(a2 - 2)

eliminate

c) 7(a2 + 2)(a2 + 2)

d) 7(a2 - 2)(a2 - 2)

ANSWER

B.

EXPLANATION

The given expression is

First factor 7 to get,

Write the expression in the parenthesis as difference of two squares:

Recall that:

We apply this to our expression to get:

you ignore the remainder, therefore the answer is y = x+2

step-by-step explanation:

you have to divide the denominator by the numerator. you can use synthetic division or long division.

[-5] .     1 .     7 .     11

x + 2 + 1/x+5