190k views
1 vote
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)

1 Answer

1 vote

ANSWER

B.


7( {a}^(2) + 2)( {a}^(2) - 2)

EXPLANATION

The given expression is


7 {a}^(4) - 28

First factor 7 to get,


7 ({a}^(4) - 4)

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


7 (({ {a}^(2) )}^(2) - 4)

Recall that:


{x}^(2) - {y}^(2) = (x + y)(x - y)

We apply this to our expression to get:


7 (({ {a}^(2) )}^(2) - {2}^(2) ) = 7( {a}^(2) + 2)( {a}^(2) - 2)

User K Guru
by
8.0k points

Related questions

asked Jul 10, 2020 205k views
Pseudoremy asked Jul 10, 2020
by Pseudoremy
7.6k points
1 answer
2 votes
205k views
asked Mar 27, 2021 205k views
MID asked Mar 27, 2021
by MID
7.9k points
1 answer
1 vote
205k views
1 answer
1 vote
82.9k views