# How do you foil (x-1)^2?

Jul 12, 2018

${\left(x - 1\right)}^{2} = {x}^{2} - 2 x + 1$

#### Explanation:

FOIL is a mnemonic to help remember which combinations of terms need to be combined to evaluate the product of two binomials.

In our example, ${\left(x - 1\right)}^{2} = \left(x - 1\right) \left(x - 1\right)$ can be evaluated as follows:

$\left(x - 1\right) \left(x - 1\right) = {\overbrace{x \cdot x}}^{\text{First" + overbrace(x * (-1))^"Outside" + overbrace((-1)*x)^"Inside" + overbrace((-1) * (-1))^"Last}}$

$\textcolor{w h i t e}{\left(x - 1\right) \left(x - 1\right)} = {x}^{2} - x - x + 1$

$\textcolor{w h i t e}{\left(x - 1\right) \left(x - 1\right)} = {x}^{2} - 2 x + 1$