To solve that, make a table of points for each equation:

For  we make a table of arbitrary points:
(You make up a value for one of the letters, substitute it,
and solve for the other letter.  If you don't know how to
do that post again asking how.

 x |  y
-3 | -6
 2 | -1
 6 |  3 

We plot them, like this:



Next we get a ruler and draw a straight line through those points:




Next we do the same thing with the other equation:

To solve that make a table of points for it:

For  we make a table of arbitrary points:


 x |  y
-2 |  7
 6 | -1
-4 | -7 

We plot them, like this:



Next we get the ruler and draw a straight line through those points,
too:




Next we find the coordinates of the point where thos two lines cross by 
drawing lines from the point where the two lines cross straight to the
the x-axis and straight to the y-axis, like this.  I'll draw them in
green:


 
And we see that the green linee ends up at 4 on the x axis and at 1 on
the y-axis, and so tjhe answer is x=4, and y=1 

We check by substituting 4 for x and 1 for y in both equations:

x - y = 3         x + y = 5
4 - 1 = 3         4 + 1 = 5
    3 = 3             5 = 5

Since both equations check, we know we have the correct solution.

Do the others the same way.

Edwin