Chapter 11 - Quadratic Functions and Equations - 11.1 Quadratic Equations - 11.1 Exercise Set - Page 706: 8

$t=\pm12$

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}