PLZ HELP DUE IN 30 minutes

Simplify (a/b - b/a) times (a - a^2/a+b) a - a^2/a=b is a mixed number

Gravel is being dumped from a conveyor belt at a rate of 25 ft3/min, and its coarseness is such that it forms a pile in the shape of a cone whose base diameter and height are always equal. how fast is the height of the pile increasing when the pile is 14 ft high? (round your answer to two decimal places.) ft/min

Find the rate of change for the situation.you run 7 miles in one hour and 21 miles in three hours.