You can use the elimination method.
You can have y crossed out so you can solve for x and then have x crossed out to solve for y for instance:
X - y = 8
+
X +y =4
To have y gone we have to make it equal to y - y or in this case -y + +y
So
X - y = 8
+
X + y = 4
2x = 12
———-
2. 2
X=6
Now to find y we have x crossed out.
X-y=8
X+y=4
To have x crossed out we’d do x - x
So
X-y = 8
-
X+ y = 4
-2y = 4
————-
-2. -2
Y = -2
Since coordinates go like (x,y) the system of equations for this problem is (6, -2)