A piont on a graph that works for x-y=8and x+y=-2

This is a system of equations.

x-y=8
x+y=-2

The easiest way to solve would be the elimination method because it is already set up; if you add the equations, the y cancels out and gives you:
2x=6
Further,
x=3
Given x you can find y in any equation above; x-y=8
Substitute the 3: 3-y=8
y=-5