1. Suppose a graph passes the horizontalline test: No horizontal line can be
drawn that touches the graph in more than one location. Does this mean that
the graph represents a function? If not, is there anything special about a graph
that passes the horizontal line test? Share your ideas with a classmate.

2. Dotty and Lionel are making a graph comparing a car's age with its gas
mileage. Dotty says the graph should show discrete points because the car's
age is stated in whole numbers of years. Lionel says they should make a
continuous line because age increases gradually, like time. Which student do
you agree with and why?

3. Write two linear functions, f(x) and g(x). For example, f(x) = 3x - 7 and
g(x) = -2x + 5. Then see whether f(x) - (-9(x)) is equivalent to f(x)+ g(x). Hint:
To find – g(x), just change the signs of all the terms in g(x). Discuss whether
you think your results would apply to every function