Answer:
x = (a+b)/2
y = (a-b)/2
Step-by-step explanation:
x+y=a
x−y=b
Add this two equations together to eliminate y
x+y=a
x−y=b
----------------
2x = a+b
Divide by 2
2x/2 = (a+b)/2
x = (a+b)/2
Subtract the two equations to eliminate x
x+y=a
-x+y=-b
-----------------
2y = (a-b)
Divide by 2
2y/2 = (a-b)/2
y = (a-b)/2
