F (x) = - 5x2 + 5.

A. Does the parabola open up or down?

B. Is the vertex a minimum or a maximum?

C. Identify the axis of symmetry, vertex and the y-intercept of the parabola.

A → opens down, B → maximum, C → x = 0, (0, 5) and 5

For a parabola of the form y = ax² + c

• If a > 0 then opens up and is a minimum

• I f a < 0 then opens down and is a maximum

the y - intercept = c and the vertex = (0, c)

The axis of symmetry is the y - axis, that is x = 0

f (x) = - 5x² + 5 is in this form with a = - 5 < 0 and c = 5

Thus the parabola opens down and is a maximum

The axis of symmetry is x = 0, vertex = (0, 5) and y-intercept = 5