A 75-gallon water tank is being emptied. The graph shows the amount of water in the tank a...

A 75-gallon water tank is being emptied. The graph shows the amount of water in the tank after x minutes.

(a) At what rate is the tank emptying during the first 2 minutes? During the next 3 minutes? During the last minute?

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(b) Suppose the tank is emptied at a constant rate of 10 gallons per minute. Draw the graph that shows the amount of water after x minutes. What is the equation of the graph?