How do I graph quadratic functions?

Question

owlfred · Answer

Hoot! You just asked your first question! Hang tight while I find people to answer it for you. You can thank people who give you good answers by clicking the 'Good Answer' button on the right!

anonymous · Answer

Well with quadratic functions you want to factor them so that it is easier to see where the zeros are and also how the graph enters and exits, if you have an example i would be more than glad to show you

anonymous · Answer

ok that would be great, my problem is 8x2+12x

anonymous · Answer

okay, first lets factor this quadratic,

anonymous · Answer

http://www.purplemath.com/modules/grphquad.htm

anonymous · Answer

ok, so how do you do that?

anonymous · Answer

all you have to do is substitute or assign values for your x and solve for y.

anonymous · Answer

it is a parabola.
it faces up because the leading coefficient (8)is positive.  it has zeros at 0 and -3/2 so that is where it crosses the x- axis.
the vertex is (-3/4,-9/2) so that is where it sits

anonymous · Answer

and here is a nice picture http://www.wolframalpha.com/input/?i=8x^2%2B12x

anonymous · Answer

how did you get -3/3, -9/2?