Choose all of the following equations that have a vertex that is the maximum point of the parabola. More than one answer may be chosen.
Answer
y = 3x2 + 9x - 4
y = 8x2 - 6x + 128
y = -x2 - 7x + 1
y = -4x2 + 8x - 19

Question

Choose all of the following equations that have a vertex that is the maximum point of the parabola. More than one answer may be chosen.
Answer
		y = 3x2 + 9x - 4
		y = 8x2 - 6x + 128
		y = -x2 - 7x + 1
		y = -4x2 + 8x - 19

anonymous · Answer

Need help stuck on stupid test question :X

mathmate · Answer

All vertices are either maximum or minimum of a parabola.
Parabolas that have a maximum are those that are concave downwards.
You can spot these by observing the sign of the leading coefficient (the coefficient of the x^2 term).
If the leading coefficient is positive, the parabola is concave upwards (i.e. has a minimum.)
If the leading coefficient is negative, the parabola is concave downwards (i.e. has a maximum.)
From the above list, I spot two of each.