Is potental energy in motion or not

This question awards 100 ! i really don’t want to fail i will also mark you !

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

Out of 50 students surveyed, 16 have a dog. based on these results, predict how many of the 280 students in the school have a dog.