options: Calculate and interpret the average rate of change of a function (presented symbolically or as a table) over a specified interval. Estimate the rate of change from a graph.

Relate the domain of a function to its graph and, where applicable, to the quantitative relationship it describes.  For example, if the function h(n) gives the number of person-hours it takes to assemble n engines in a factory, then the positive integers would be an appropriate domain for the function.

For a function that models a relationship between two quantities, interpret key features of graphs and tables in terms of the quantities, and sketch graphs showing key features given a verbal description of the relationship. Key features include: intercepts; intervals where the function is increasing, decreasing, positive, or negative; relative maximums and minimums; symmetries; end behavior; and periodicity.
problem_activity: A store is having a sale to clear out merchandise. If you spend between $0 and $100, you can take 15% off of your total. If you spend over $100, you can take 25% off of your total.
Write an equation to represent your discounted total if you spend between $0 and $100.
Write an equation to represent your discounted total if you spend over $100.
Which graph best represents the situation?
[IMG]


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