Question

Predict what the graph of the following quadratic function will look like. (If you have a graphing calculator, you can use it to verify your prediction.)

y = 0.3 x squared minus 5

a.
Upward facing parabola-shaped; y-intercept (5, 0); symmetrical with respect to the y-axis
b.
Downward facing parabola-shaped; y-intercept (0, -5); symmetrical with respect to the y-axis
c.
Upward facing parabola-shaped; y-intercept (0, -5); symmetrical with respect to the y-axis
d.
Downward facing parabola-shaped; y-intercept (5, 0); symmetrical with respect to the y-axis

Answer 1

c. Upward facing parabola-shaped; y-intercept (0, -5); symmetrical with respect to the y-axis

Explanation:

The positive leading coefficient tells you the graph opens upward. (Eliminates B and D)

The constant -5 tells you the y-intercept is -5. (Eliminates A, which shows an x-intercept, not a y-intercept.)

The function is a vertical translation and scaling of the parent function y=x². There is no translation left or right, so the axis of symmetry remains the y-axis.

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The correct description is ...

• opens upward
• y-intercept (0, -5)
• axis of symmetry is the y-axis