Question 1011735
There is obviously no solution,
because {{{x-y}}} cannot equal {{{4}}} and equal {{{13}}} at the same time.
By elimination, you would multiply {{{x-y=4}}} times {{{(-1)}}} ,
to get {{{-x+y=-4}}} ,
and then add {{{x-y=13}}} , getting
{{{-x+y+x-y=-4+13}}} ---> {{{0=9}}} .
so there is no pair (x,y) that will satisfy both equations
(unless you know of a planet where {{{0=9}}} ).