If water depths of 12.1, 1.6, -4.1 and -4.8 cm are observed at clock times 24, 36, 48 and 60 sec, then at what average rate does the depth change during each time interval?

Sketch a graph of this data set and use a sketch to explain why the slope of this graph between 36 and 48 sec represents the average rate at which depth changes during this time interval.

 If f(x) = x², give the vertex and the three basic points of the graphs of f(x--.75), f(x) - -1.65, .2 f(x) and .2 f(x--.75) + -1.65. Quickly sketch each graph.