A.6.11.2 Comparing Two Graphs

f(x) = x(x +4)   g(x) = x(x - 4) Complete the table of values for each function below. Then, determine the x-intercepts and vertex of each graph. Explain how you know.

Plot the points from the tables on the same coordinate plane. (Consider using different colors or markings for each set of points so you can tell them apart.) Then, make a couple of observations about how the two graphs compare.

Compare the graphs of the functions given by p(x) = (x - 1)(x - 3) and q(x) = (x + 1)(x + 3).

1. What will their x-intercepts be?
2. Where will the x-coordinate of the vertex of each graph be?
3. How do we find the y-coordinate of each vertex?
4. The y-intercept of both graphs is (0, 3). What is another point on each graph with the same y-coordinate?”