rearrange the first equation
2x + y = 20
take away 2x from both sides
y = 20 - 2x
substitute this y value into the second equation
6x - 5(20 - 2x) = 12
6x -100 +10x = 12
add 100 to both sides
6x + 10x = 112
16x = 112
divide both sides by 16
x = 7
Substitute this x value into the first equation to get y.
2(7) + y = 20
14 + y = 20
take away 14 from both sides
y = 6
So, y = 6 and x = 7
