Can someone please help me with these 4 questions?

Assemble the proof by dragging tiles to the statements and reasons column

Which undefined geometric term is described as a location on a coordinate plane that is designed by an ordered pair (x,y) ?

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