This is Bridge Algebra 2 stuff. Well you see that 2x+y=8 and x-1=y. To slove for y you have to slove for x first to find y. So 2x+x-1=8 ( the reason I did that is because there is a y in that equation and I placed it on that equation) now lets slove this equation for x. So 3x-1=8( I add 2x with x) 3x=9 ( I made -1 a positive one and add it to 8) x=3 ( I divided 9/3 to get 3). Now that you have slove x we will use x to slove for y. So 3-1=y, 2=y. Your answer is y=2.