Answer
$(-3,-3)$
Work Step by Step
Adding the two equations will eliminate y.
The resulting equation:
$2x=-6\qquad/\div 2$
$x=-3$
Back substitute into one of the initial equations:
$x-y=0$
$-3-y=0\quad/+y$
$-3=y.$
Solutions are ordered pairs (x,y):
$(-3,-3)$
Check graphically by graphing both lines in the same window and determining the intersection (see image).