Answer
$(-1,-2) $ is not a solution of the system
Work Step by Step
A solution of a system of two equations in two variables is an ordered pair of numbers that makes both equations true.
Substituting $x=-1, y=-2$ into each equation,
$ x+3y=-7$
$ (-1)+3(-2)\stackrel{?}{=}-7$
$-1-6=-7,\qquad $...the first equation is true for $(-1,-2)$
$3x-2y=12$
$3(-1)-2(-2)\stackrel{?}{=}12$
$-3+4\neq 12\qquad $...the second equation is not true for $(-1,-2)$
$(-1,-2) $ is not a solution of the system.