Question

Multiply (2x + 8)(4x + 7).

A. 8x2 – 18x – 56
B. 8x2 + 46x + 56
C. 8x2 + 56
D. 8x2 + 18x – 56

Answer 1

(2x + 8)(4x + 7) = 2x(4x + 7) + 8(4x + 7) = 8x^2 + 14x + 32x + 56 =
8x^2 + 46x + 56 <==

Answer 2

B.
`8x^2+46x+56`

Explanation:

We must multiply the elements of each parenthesis by the terms of the other parenthesis, We will have the following:

`(2x + 8)(4x + 7)=(2x)(4x)+(2x)(7)+(8)(4x)+(8)(7)\\(2x + 8)(4x + 7)=8x^2+14x+32x+56\\`

We have two terms with x, so we add them:

`(2x + 8)(4x + 7)=8x^2+46x+56`

So the correct answer is B.