De-orbit maneuvers are usually done to lower the perigee of the orbit to 60 miles (or less). The Orbiter is captured and re-enters as it passes into the atmosphere at this altitude.

There is a change of 1 mile for every 2 feet per second (fps) change in velocity when you are below a 500-mile altitude above the Earth.

Determine the change in velocity (delta-V) that the Shuttle will need to make if it is at an altitude of 220 miles above the Earth at apogee and 212 miles above the Earth at perigee, and needs to drop the perigee to an altitude of 60 miles.

Your answer needs to be in feet per second.

That looks more a question for the homework board.
And possibly the reason why Nasa uses computers.
But what has it to do with astronomy?