Question

Which is the completely factored form of 4x2 + 28x + 49?

O
(x + 7)(4x + 7)
4(x + 7)(x + 7)
(2x + 7)(2x + 7)
2(x+7)(x + 7)
.

Answer 1

3) (2x+7)(2x+7)

Explanation:

FOIL (first, outer, inner, last) it back out, you get 4x^2 + 14x + 14x + 49 which simplifies to the original.

Answer 2

(2x + 7)(2x + 7)

Explanation:

`4 {x}^(2) + 28x + 49 \\ = 4 {x}^(2) + 14x + 14x + 49 \\ = 2x(2x + 7) + 7(2x + 7) \\ = (2x + 7)(2x + 7)`