Find the determine number of solution: y=x-7 x-y=-4

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

We just started the introduction into circles and i have no idea how to do this.

What is the radical expression that is equivalent to the expression 27 1 over 5?