Could someone me solve this problem?

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

What numbers are included in the set of integers? what numbers are not included?

I'm a polygon i have no parallel lines i am formed 3 line segments i have one right angle two of my angles are angles what am i