What is the simplified form of the expression? 2sqrt18 - 5sqrt32

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

Evaluate the expression for the given value of the variable 7a - 4a for a =8

What is the range for 31,39,29,34,37,24,36,33,34,28