warned: You must use fractions to help discern which is correct. Let’s say the x-intercepts take
place at x = and x = . Rewriting those two expressions means that the factors are
and . If you FOIL out the terms, you end up with x^2 – x + . Remember, the parabola
opens downward, so you must multiply by –1 to each term to yield –x^2 + x − . Your values
of a and c are now –1 and – , respectively. Multiply the two values and you get , which
allows you to eliminate (A) and confidently choose (C). (And that was worth only 1 point!
Embrace the POOD!)
- C Figure out the points that will be on the graph from the data given: (0, 0), (1, 5), (2, 10), (3, 15),
(4, 20). Draw a line through or close to these points to get an idea of what the graph will look
like. Then use POE. The line is linear, not quadratic, so you can eliminate (D). It is also clear
that the line begins at the origin, so the y-intercept will be 0. This will eliminate (A). A slope of
25 is far too big—Ballpark—so you can eliminate (B), leaving (C).
