Question 105380
If you didn't know, you can not only add numbers and variables but whole equations!

To demonstrate this we can use your problem:
x + y = 6
x – y = 4

All you do to do this by addition, would be to add:

(x+y)+(x-y)=(6)+(4)

This would simplify into:
2x = 10
x = 5

Substitution:

5 - y = 4

Subtract 5 on both sides to get

-y = 4 - 5
 
Simplify:
-y = -1
y = 1

The solution is: (5,1)