[tex]3x\text{ -}\frac{1}{9}y\text{ = 18}[/tex]
simply substitute y = 27, in the above equation
[tex]3x\text{ -}\frac{1}{9}(27)\text{ = 18}[/tex]3x - 3 = 18
add 3 to both-side of the equation
3x - 3 + 3 = 18 + 3
3x = 21
divide both-side of the equation by 3
3x/3 = 21/3
x=7
Hence the value of x is 7