help please

3. A pulley is on the edge of dock 8 feet above the water. A rope is being used to pull in a boat. The rope is attached to the boat at water level. Boat X a) Let x = the distance from dock of the boat and r = the length of the rope. Write an equation relating x and r. b) Differentiate the equation implicitly with respect to time, t. c) If the rope is being pulled in at a rate of 1 foot per second. At what velocity is the boat approaching the dock at the instant boat is 6 feet from the dock