Solve for x I am totally confused on this can someone help me asap

Two parallel lines are crossed by a transversal.what is value of x

The variable in a relation who’s value depends on the value of the independent variable is called what?

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