Question

How? (2x^2 - 3x - 4)(x + 7)
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Answer 1

`2 {x}^(3) + 11{x}^(2) - 25x - 28`

Explanation:

Using foil method, Multiply the first term

`2 {x}^(2) * x = 2 {x}^(3)`

Next, Multiply the Outer term in each parenthesis. (2x^2 and 7

`2 {x}^(2) * 7 = 14 {x}^(2)`

`2 {x}^(2) * 7 = 14 {x}^(2) \: \: \: 3x * - x = - 3x`

Then, Multiply the Inner Terms (-3x,-4,7) in each parenthesis

`- 3x * 7 = - 21x`

`- 4 * x = - 4x`

Then multiply the last term (-4 and 7).

`- 4 * 7 = - 28`

Combine it you have

`2 {x}^(3) + 14 {x}^(2) - 3 {x}^(2) - 21x - 4x - 28`

which simplify to

`2 {x}^(3) + 11 {x}^(2) - 25x - 28`