x+y=72
x-y=48
Solve for one of the variables.
x=48+y
Then plug into the other equation and solve.
(48+y)+y=72
48+2y=72
2y=24
y=12
Use that answer in one of the formulas to find the other variable.
x+12=72
x=60
You can plug the answers into the original formulas to check the answers.
