Chapter 5 - Polynomials and Factoring - 5.6 Factoring: A General Strategy - 5.6 Exercise Set - Page 344: 16

$2(7t+3)(7t-3)$

Factoring the $GCF= 2 $, then the given expression, $ 98t^2-18 $ is equivalent to \begin{array}{l} 2(49t^2-9) .\end{array} Using $a^2-b^2=(a+b)(a-b)$ or the factoring of the difference of $2$ squares, then the complete factored form of the expression above is \begin{array}{l} 2(7t+3)(7t-3) .\end{array}