It should be,
4x-8=2x-10 because you substitute that for y.
Now you do,
4x-2x because you do the opposite of the positive 2x as you bring it to the other side.
That is,
2x-8=10 now you bring the 8 to the other side.
2x=10+8 I added it because I do the opposite and it is a negative 8 so I add.
2x+18 now divide
x=9 that's the answer.
13.1......... I believe this is the correct answer
