How do you tell whether the graph opens up or down, find the vertex and the axis of symmetry of #y=5(x+5)(x-2)#?
1 Answer
Dec 22, 2017
opens upward
and has an axis of symmetry
Explanation:
A quadratic opens upward if the coefficient of
and downward if the coefficeint of
An expansion of
That is the coefficient of
Since this is greater than zero the graph would open upward.
For a quadratic in standard form which crosses the X-axis, the axis of symmetry is
where
The x-intercept values are the values of
In this case (obviously)
The midpoint between
so the axis of symmetry is
