You're fist step is to choose a way to solve this system. My favorite is substitution. Plug in -x+8 for y in the second equation. The reason you are able to do this is because the substitution property which you learn in geometry. So now you have the equation -x+8=4x-7. Now add seven to both sides and subtract x from both sides. You should be left with 15=3x. Now you simply divide by 3 and the answer is x=5
