# How do you solve 5 - x^2 = 20?

Jun 1, 2017

$x = - 3.873$

#### Explanation:

$5 - {x}^{2} = 20$

$- {x}^{2} = 20 - 5$

$- {x}^{2} = 15$

$- x = \sqrt{15}$

$- x = 3.873$

color(blue)(x = -3.873

We can now prove our answer by substituting $x$ for $- 3.873$

$5 - {x}^{2} = 20$

$5 - - {3.873}^{2} = 20$

$5 + {3.873}^{2} = 20$

$5 + 15 = 20$