If f(x) = x², what are the vertex and the three basic points of the graphs of f(x--.75), f(x) - -1.15, 4 f(x) and 4 f(x--.75) + -1.15. Quickly sketch each graph.

At clock times 11.2, 16.8, 22.4 and 28 sec, we observe water depths of 39.9, 36.2, 33.6 and 32.2 cm.

• At what average rate does the depth change during each time interval?

Sketch a graph of depth vs. clock time.

• Use a sketch to explain why the slope of this graph between 11.2 and 16.8 sec represents the average rate at which depth changes during this time interval.