Solve the following related rates:
a) A 14 foot ladder is leaning against a wall. If the top slips down the wall at a rate of 3 ft/s, how fast will the foot be moving away from the wall when the top is 10 feet above the ground?
b) A price p in dollars and demand x for a product are related by
2x^2+4xp+50p^2=600
If the price is increasing at a rate of 2 dollars per month when the price is 10 dollars, find the rate of change of the demand.