Is this function linear or nonlinear? y=2x2−4 nonlinear linear

Monica build a remote control toy airplane for science project to test the plane she launched it from the top of a building the plane travel a horizontal distance of 50 feet before landing on the ground a quadratic function which models the height of the plane in feet relative to the ground at a horizontal distance of x feet from the building is shown

What is the reflection image of (5,-3) across the line y = -x?

Solve this system of equations. 12x − 18y = 27 4x − 6y = 10