To eliminate one variable and allow to calculate the other variable you need to multiply one or both equations so that the coefficients of one variable can be eliminated using addition or subtraction between the adjusted equations. But first we need to simplify the second equation because we can take out a common factor 4: x-9y=25. In this system we now have 6x and x, so we can multiply the revised second equation by 6 so that we have 6x in common between the equations: 6x-5y=3; 6x-54y=150. Subtract the second from the first: 49y=-147 (or if we subtract the first from the second we get -49y=147, which is the same thing). 49 goes into 147 3 times: y=-3. Take either equation and substitute y=-3: 6x+15=3 or x+27=25. We get 6x=-12 or x=-2, which is the same answer for x whichever equation we use. So the solution is x=-2 and y=-3.