From equation 1 x=2-6y. Where x appears in equation 2 we replace it with this value of x. This changes equation 2 to 5(2-6y)+4y=36. Open the brackets: 10-30y+4y=36, so 10-26y=36, and 10-36=26y. So 26y=-26 and y=-1. We can now substitute this value of y in x=2-6y, so x=2+6=8. Check out these values for x and y in the original equations: 8-6=2 and 40-4=36. Correct!