Answer
$\color{blue}{\left\{-8, 8\right\}}$
Work Step by Step
RECALL:
$a^2-b^2=(a-b)(a+b)$
Since $64=8^2$, the given equation can be written as:
$t^2-8^2=0$
Factor the binomial using the formula above to obtain:
$(t-8)(t+8)=0$
Use the Zero-Factor Property by equating each factor to zero to obtain:
$t-8=0$ or $t+8=0$
Solve each equation to obtain:
$t-8=0
\\t=0+8
\\t=8$
or
$t+8=0
\\t=0-8
\\t=-8$
Therefore, the solution set is $\color{blue}{\left\{-8, 8\right\}}$.
