Answer
The solution set is $\left\{-2, 2\right\}$.
Work Step by Step
Divide 7 on both sides to obtain:
$x^2 = 4$
Add $-4$ on both sides to obtain:
$x^2-4 = 0
\\x^2-2^2=0$
RECALL:
A difference of two squares can be factored using the formula:
$a^2-b^2=(a-b)(a+b)$
Factor the difference of two squares to obtain:
$(x-2)(x+2)=0$
Equate each factor to 0, and then solve each equation to obtain:
$x-2=0 \text{ or } x+2 = 0 \\\
x=2 \text{ or } x=-2$
The solution set is $\left\{-2, 2\right\}$.
