Question

Expand and combine like terms.
(5 - 2x^4) (5 + 2x^4) =

Answer 1

`25 - 4x^8`

Explanation:

1)
`(5 - 2x^4) (5 + 2x^4)`

Simplify using
`(a - b)(a + b) = a^(2) - b^(2)`

2)
`5^(2) - (2x^4)^(2)`

Evaluate the power

3)
`25 - (2x^4)^(2)`

4)
`25 - 4x^8`

Answer 2

25 - 4x^8

Explanation:

Use FOIL here.

Combine the first terms of both expressions.

5 * 5 = 25

Combine the outer terms of both expressions.

2x^4 * 5 = 10x^4

Combine the inner terms of both expressions.

-2x^4 * 5 = -10x^4

Combine the last terms of both expressions.

-2x^4 * 2x^4 = -4x^8

(a^x * a^y = a^(x+y).)

Now add those terms.

25 + 10x^4 - 10x^4 - 4x^8

Combine like terms to get:

25 - 4x^8.