If f(x) = x², what are the vertex and the three basic points of the graphs of f(x--1.75), f(x) - -1.15, 5 f(x) and 5 f(x--1.75) + -1.15. Quickly sketch each graph.

At clock times 37.6, 56.4, 75.2 and 94 sec, we observe water depths of -7.6, -23.8, -32.9 and -34.9 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 37.6 and 56.4 sec represents the average rate at which depth changes during this time interval.