3x + 6y = 18 -6y
3x = 18 - 6y Divide by 3
3x/3=18/3-6y/3 Simplify
x=6-2y
Now we check by plugging in the value of x.
3(6-2y)+6y=18 simplify
18-6y+6y=18 simplify more
18=18.
NOW we know for sure that this is correct
