#### Answer

$t=\pm12$

#### Work Step by Step

Since $x^2=a$ implies $x=\pm\sqrt{a}$ (the Square Root Principle), the solutions to the given equation, $
t^2=144
,$ are
\begin{array}{l}\require{cancel}
t=\pm\sqrt{144}
\\\\
t=\pm\sqrt{(12)^2}
\\\\
t=\pm12
.\end{array}