Quadratics

[DamselFly]

Okay I really need help with this. My teacher(or rather the student teacher...) has the computer teach us... So basically we learn math from powerpoints on our own that teach us absolutely nothing. Anyways, I need help with quadratics. I looked up a few sites on the internet and started to pick most of the information up, but when I looked at the paper we we're given it doesn't work.

One Example is this:

2x^2 + 9x + 8 = 0

[*- the ^2, means the unit is squared.]

I learned to 'factor' it with a chart thing (almost like a tic-tac-toe board) but the numbers won't add up. Can someone please explain how to do this problem. If I understand this much at least, I'm pretty sure I can work out the others.

[qwertysaur]

You need to use the quadratic formula. That cant be factored.

[rubah]

the quadratic formula of course being the abhorrant x = -b ± sqrt(b^2-4ac)/2a

where a = the coefficient in front of the the x squared, b = coefficient in front of x, and c any constants left over.

It is evil and must be used sparringly. Learn to factor perfectly then you will have reduced the number of times you have to apply the quadratic equation. (and increased your lifespan)

[DamselFly]

Thanks I was stumped there. I remember learning that a year or two back now that you mention it.

[Heath]

I never really had much of an issue with the quadratic formula. Naturally graphs and factorising them are nicer, but the formula isn't that bad.