Question 175203
(x - y = 4) & (x + y = 2). 

Rewrite each equation to slope y-intercept form

x-y=4  Can be rewritten as y=x-4 (Equation #1)

x+y=2  Can be rewritten as y=2-x  (Equation #2)

REplace equation #2 into Equation #1

so 2-x=x-4  

Gather all like terms on the same side of the equation

So 2x=6

Solve for x

x=3

Substitute x=3 into Equation #2

y=2-3=-1

So the solution is (3,-1)

I hope that this helps.  This is a general approach that should work with all similar problems.