Question

For y = x2 + 6x - 16,

Determine if the parabola opens up or down.
State if the vertex will be a maximum or minimum.
Find the vertex.
Find the x-intercepts.
Describe the graph of the equation.

Answer 1

up

Answer 2

as coeffi. of x^2 is positive , it opens up.
hence the vertex will be minimum.
vertex(-b/2a , -D/4a)
x-int. ,put y=0.

Answer 3

The Parabola opens up because the term with X^2 is positive
If it was negative then it would open down.

Answer 4

Yep, you're absolutely correct! Try plotting a few equations on here: http://www.mathsisfun.com/data/function-grapher.php
You should get the hang of it in no time.

Answer 5

y = x2 + 6x - 16
y = (x + 3)^2 - 9 - 16
y = (x + 3)^2 - 25
notice for all values of x > 2 y is positive therefore it must open up