Answer: x=9
Explanation: begin by substituting or replacing “y” with 4x since y=4x. This should give you the new equation of 4x=8x-36. Then subtract 8x from both sides so that it will cancel out 8x and leave you with 4x-8x=-36. Then combined like terms to then give you -4x=-36. Lastly, divide each side by -4 which will give you the answer of x=9 because when you divide -4 by -36, two negatives cancel each other out and leave you with a positive outcome.