Here are the two equations:
2x - y = 2
x + 2y = 18.5
By substitution.
2x - y = 2
y = 2x - 2
Substitute y to the second equation: x + 2y = 18.5
x + 2(2x-2) = 18.5
x + 4x - 4 = 18.5
5x = 22.5
x = 4.5
get y by substituting x to 2x - y = 2
2(4.5) - y = 2
y = 7
So x = 4.5, y = 7