Answer
$(3,-1) $ is 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 $x=3, y=-1$ into each equation,
$ 3x-4y=13$
$ 3(3)-4(-1)\stackrel{?}{=}13$
$9+4=13,\qquad $...the first equation is true for $(3,-1)$
$6x-8y=26$
$6(3)-8(-1)\stackrel{?}{=}26$
$18+8=26\qquad $...the second equation is true for $(3,-1)$
$(3,-1) $ is a solution of the system.