Will give ! graph the equation on the coordinate plane y=−2x

Can somebody me out with this question

To solve the system of equations below, grace isolated the variable y in the first equation and then substituted into the second equation. what was the resulting equation? 3y=12x x^2/4+y^2/9=1

Given: m∠ adb = m∠cdb ad ≅ dc prove: m∠ bac = m∠bca lol