I'm pretty sure it would be 6 (x - 4y) = 36.
Try to get the variable you are looking for by itself by either adding, subtracting, multiplying, or dividing all the things next to it and get it to the other side. once you are done substitute that into the other equations and solve. Then the answer you get you plug it in to the first simplified equation
8x-27=3x+58, get all x values on one side and constants on the other 5x=85, now divide both sides by 5. We get the answer of x=17