$t=15$ or $t=-11$
Work Step by Step
$t^2-4t-165=0$ $t^2-2.x.2+4 -169=0$ $(t-2)^2=169$ $(t-2)^2=(13)^2$ $t-2=\pm 13$ $t-2=13$ or $t-2=-13$ $t=15$ or $t=-11$
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