Elementary and Intermediate Algebra: Concepts & Applications (6th Edition)

$t=\left\{ -10,10 \right\}$
Factoring the given equation, $x^2-100=0 ,$ results to \begin{array}{l}\require{cancel} (x+10)(x-10)=0 .\end{array} Equating each factor to zero (Zero Product Principle), then the solutions to the equation, $(x+10)(x-10)=0 ,$ are \begin{array}{l}\require{cancel} x+10=0 \\\\ x=-10 ,\\\\\text{OR}\\\\ x-10=0 \\\\ x=10 .\end{array} Hence, $t=\left\{ -10,10 \right\} .$