Which name could be used to describe this group of solid shapes?

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

(! ) three cylinders have a height of 8 cm. cylinder 1 has a radius of 1 cm. cylinder 2 has a radius of 2 cm. cylinder 3 has a radius of 3 cm. find the volume of each cylinder

In the polynomial below, what number should replace the question mark to produce a difference of squares? x2 + ? x - 36