Find the derivative of x + xy + y = 27 8. A conical tank 20 feet in diameter and 30 feet tall is leaking water at a rate of 5m cubic feet per hour. At what rate is the water level dropping when the water is 15 feet deep? (Show a complete solution on the back.) 10. Find the area between the curve y = x-4x-7x+10 and the x-axis over the interval from [0, 1].