Question

What is the product?
(2x-1)(x+4)
O 2x24
O 2xả44
O 2x²+7x-4
O 2x²-7x-4

Answer 1

`C. 2x^2+7x-4`

Explanation:

1) Distribute.

`(2x-1)(x+4)\\2x(x+4)-1(x+4)`

2) Distribute.

`2x(x+4)-1(x+4)\\2x^2+8x-1(x+4)`

3) Distribute.

`2x^2+8x-(x+4)\\2x^2+8x-x-4`

4) Combine like terms.

`2x^2+8x-x-4\\2x^2 + 7x - 4`

Answer 2

Answer: The third option, O 2x²+7x-4

Explanation:

We can use the "FOIL" method. We take the following four sets, multiply them together, then add them for our final answer.

-> first

-> last

-> inner

-> outer

What does this look like mathematically?

-> first = (2x - 1)(x + 4) = 2x * x = 2x²

-> last = (2x - 1)(x + 4) = -1 * 4 = -4

-> inner = (2x - 1)(x + 4) = -1 * x = -x

-> outer = (2x - 1)(x + 4) = 2x * 4 = 8x

-

2x² - 4 - x + 8x

2x² + 7x - 4

O 2x²+7x-4