How do you solve 4x^2=28?

Apr 19, 2017

${x}^{2} = 7$ or $x = \sqrt{7}$

Explanation:

Divide both sides by 4 (first step):

${x}^{2} = \frac{28}{4}$
${x}^{2} = 7$

Take square root (of both sides):
$x = \sqrt{7}$

This is your answer: $x = \sqrt{7}$

Apr 19, 2017

$x = \pm \sqrt{7}$

Explanation:

$\textcolor{b l u e}{\text{Isolate " x^2" by dividing both sides by 4}}$

$\frac{\cancel{4} {x}^{2}}{\cancel{4}} = \frac{28}{4}$

$\Rightarrow {x}^{2} = 7$

$\textcolor{b l u e}{\text{take the square root of both sides}}$ remembering that the square root of a number can have a positive/negative value.

$\sqrt{{x}^{2}} = \textcolor{red}{\pm} \sqrt{7}$

$\Rightarrow x = \textcolor{red}{\pm} \sqrt{7}$