PSAT/NMSQT Prep 2022 - Eggert M.D., Strelka A. 2022
On test day
Quadratics
Passport to advanced math
Remember that the PSAT doesn’t ask you to show your work. If you find the algebra in a question challenging, there is often another way to get to the answer.
Try to answer this question first by setting the two functions equal to each other and then by plugging the values of one of the intersection points into one of the functions. Which approach do you find easier? There’s no right or wrong answer—just remember your preferred approach and try it first if you see a question like this on test day.
30. The functions f(x) = 2x2 − 5 and g(x) = 6x2 − 7 are graphed in the xy-plane above. The points where the two functions intersect are (z, −4) and (−z, −4). What is the value of z?
A. 
B.
C.0.8
D. 1.2
The correct answer and both ways of solving can be found at the end of this chapter.