# How do you solve x^{2} - 8= 0?

May 23, 2018

$x = \pm 2 \sqrt{2}$

#### Explanation:

$\text{isolate "x^2" by adding 8 to both sides}$

${x}^{2} = 8$

$\textcolor{b l u e}{\text{take the square root of both sides}}$

$\sqrt{{x}^{2}} = \pm \sqrt{8} \leftarrow \textcolor{b l u e}{\text{note plus or minus}}$

$\Rightarrow x = \pm 2 \sqrt{2}$

May 23, 2018

$x = \pm 2 \sqrt{2}$

#### Explanation:

${x}^{2} - 8 = 0$

first add 8 to both sides:

${x}^{2} = 8$

now take the square root of both sides, remember you must use $\pm$ the square root on the right side:

$\sqrt{{x}^{2}} = \pm \sqrt{8}$

$x = \pm 2 \sqrt{2}$

May 23, 2018

$x = \pm 2 \sqrt{2}$

#### Explanation:

color(blue)(x^2-8=0

To, solve this, we need to isolate ${x}^{2}$ in one side of the equation. To do that, we can add or subtract the same number in both sides of the equation.

Add $8$ both sides

$\rightarrow {x}^{2} - 8 + \textcolor{red}{8} = 0 + \textcolor{red}{8}$

$\rightarrow {x}^{2} = 8$

Now, take the square root of both sides,

$\rightarrow \sqrt{{x}^{\cancel{2}}} = \pm \sqrt{8}$

$\rightarrow x = \pm \sqrt{8}$

Now, take the prime factors of $8$

$\rightarrow x = \pm \sqrt{\underbrace{2 \cdot 2} \cdot 2}$

color(green)(rArrx=+-2sqrt2

Remember that $\pm$ means plus or minus