The function y = ax²
Answers are for parents and teachers.
1
Find the value of y = −3x² at x = −2.
−12
2
Find the intersection points of y = 2x² and y = x² + 9.
(3, 18), (−3, 18)
3
The parabola y = ax² passes through (2, 12). Find a.
a = 3
4
The parabola y = ax² passes through (−3, −18). Find a and say where the branches point.
a = −2; the branches point down
5
How are the graphs of y = x² and y = −x² related? Why?
They are symmetric about the Ox axis: for each x the values are equal in size and opposite in sign.