# How do you solve x^2 - 4x = 5?

May 10, 2018

$x = - 1 \text{ or } x = 5$

#### Explanation:

$\text{since the coefficient of the "x^2" term is 1}$

${x}^{2} - 4 x - 5 = 0 \leftarrow \textcolor{b l u e}{\text{in standard form}}$

$\text{the factors of - 5 which sum to - 4 are - 5 and + 1}$

$\Rightarrow \left(x - 5\right) \left(x + 1\right) = 0$

$\text{equate each factor to zero and solve for x}$

$x + 1 = 0 \Rightarrow x = - 1$

$x - 5 = 0 \Rightarrow x = 5$