Question

Solve the system of equations for x and y.
x+y=a
x−y=b

Answer 1

x = (a+b)/2

y = (a-b)/2

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