What is the unit rate and each rate for 420 miles in 7 hours

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

Can someone show me step by step how to do this?

Tim knows the volume and base area of a wooden chest that is in the shape of a rectangular prism. if the volume is 524 cubic unit and the base area is 15 square unit, what is the height of the chest? 124 unit 1124 units 112 unit 1112 units