# How do you solve x^2 - 4x = 0?

Mar 28, 2018

$\left(x + 2 \sqrt{x}\right) \left(x - 2 \sqrt{x}\right)$

#### Explanation:

= ${x}^{2} - 4 {\left(\sqrt{x}\right)}^{2}$

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

*Use* ${a}^{2} - {b}^{2} = \left(a + b\right) \left(a - b\right)$

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