Answer:
y=2
Explanation:
If I interpreted what you wrote correctly, the equations were 5x-4y=7 and x=5-y. Given these equations, we can substitute the x=5-y into the other equation due to it quite literally being equal to x. When you substitute the x-equation in, it reads 5(5-y)-4y=7. Distribute the 5 into the (5-y) to get 25-5y-4y=7. Combine like terms to get 25-9y=7. Next, subtract the 25 from each side to isolate the -9y. This leaves yoy with -9y= -18. Divide by -9 on each side to isolate and find y. This leaves you with y=2. You can check your work by substituting the y=2 into the second equation to find x and then use the x and y to check your solution in the first equation. :)