Set it up like:
x + y = 84
x - y = 32
You can add the equations to eliminate y:
2x + 0y = 116
2x = 116; now divide by 2 to isolate the x, and you get x= 58
Now plug x= 58 into either equation and solve for y.
58 + y = 84; subtract 58 from both sides to isolate y, and you get y= 26