Question

What is (x+3) (x-7)?

Answer 1

`x^2-4x-21`

Explanation:

`\left(x+3\right)\left(x-7\right)`

Apply FOIL method:-

`\left(a+b\right)\left(c+d\right)=ac+ad+bc+bd`

`\left(x+3\right)\left(x-7\right)`

`xx+x\left(-7\right)+3x+3\left(-7\right)`

`=x^2-4x-21`

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Answer 2

We can use FOIL to solve this:

F - First

O - Outer

I - Inner

L - Last

`= (x * x)+(x * - 7)+(3 * x)+(3 * - 7)`

`= {x}^(2) + - 7x + 3x - 21`

`= {x}^(2) - 4x - 21`