attack_panic
·
5y
Another solution is to solve one equation for one variable, and plug that into the other equation.
x + y = 66
x = 66 - y
(66 - y) - y = 18
66 - 2y = 18
-2y = 18 - 66
-2y = -42
-2y/-2 = -42/-2
y = 24
Now that you have y, plug that into the first equation and solve for x.
x + 24 = 66
x = 66 - 24
x = 42
Then plug your two answers into both original equations to verify.
x + y = 66
42 + 24 = 66
66 = 66 check
x - y = 18
42 - 24 = 18
18 = 18 check
