Question 37232
We can solve this system by substitution:

x-y=3, From this equation we get x=3+y
2x-y=-1, Substituting  in the second equation we get 2(3+y)-y=-1, 
solving 6+2y-y=-1, y=-1-6, y=-7,
And replacing the obtained value in the equation x=3+y, we obtain x=3+(-7), 
x=-4 

The solutions to the system are x=-4, y=-7.
{{{ graph( 300, 200, -6, 5, -10, 10, x-3, 2x+1) }}}