If f(x) = x², what are the vertex and the three basic points of the graphs of f(x- 1.75), f(x) - -.15, 4 f(x) and 4 f(x- 1.75) + -.15. Quickly sketch each graph.

At clock times 10.2, 15.3, 20.4 and 25.5 sec, we observe water depths of 37.2, 34.2, 32.5 and 32 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 10.2 and 15.3 sec represents the average rate at which depth changes during this time interval.