${x}^{2}=64$
Move the constant to the left-hand side and change its sign${x}^{2}-64=0$
Use ${a}^{2}-{b}^{2}=\left( a-b \right)\left( a+b \right)$ to factor the expression$\left( x-8 \right) \times \left( x+8 \right)=0$
When the product of factors equals $0$, at least one factor is $0$$\begin{array} { l }x-8=0,\\x+8=0\end{array}$
Solve the equation for $x$$\begin{array} { l }x=8,\\x+8=0\end{array}$
Solve the equation for $x$$\begin{array} { l }x=8,\\x=-8\end{array}$
The equation has $2$ solutions$\begin{array} { l }x_1=-8,& x_2=8\end{array}$