algebra/trig2

well as it goes, i forgot most of what i sleep threw last year due to staying up multiple days in a row, so this will be my all purpose cry for help =D . first order of business, does anyone know how to do this problem, and if you do can you give me the steps to do it?

x^2-2x>0

^i am sure i look like an idiot right now lol.

Yes you do look like an idiot. BUT luckily Im here to help

Lol JK

What exactly is the question asking?

i need to find x, and i just cant get my head quite around foiling, i blame the idiot who sits next to me and needs the teacher attention 24/7

x^2-2x>0
x(x-2)>0

Break it into intervals (-∞,0)∪(0,2)∪(2,∞+)
and you pick a number from each interval to check which satisfy it.
so.....
Pick -10 for the first interval
(-10)(-10-2)>0
true! thus we know (-∞,0) is one interval

Pick 1 for(0,2)
(1)(1-2)>0
false!
thus we know (0,2) is not one interval

pick 100 for the final interval
(100)(100-2)>0 true!

Thus the answer is (-∞,0]∪[2,∞+)
[ means inclusive and ( means exclusive
If you have any questions post

x^2-2x>0
x(x-2)>0
x>2

x^2-2x<0
x(x-2)<0
x=1

This is if I remember everything correctly. I asked Lev to check.

And he did it before me.

Take Lev's answer. My brain is still on vacation mode. Espcially with this lack of HW.

@Lev: You don't multiple the inequality by -1 to get the other answers?

What grade are you in Ahmed? Your only in Algebra 2 :O

I'm in AP Calculus AB

You should trust me...I told Ahmed of a dude who teaches this stuff listen to him....I am not sure if i can say his name

OK Lev

This isn't really hard...it's just that my brain is a bit rusty at the moment. Still need to go into school mode.

thanks Lev,thanks to you i see what i have been missing =D

Oh I remember doing this with Arjun now when he used to draw +s and -s on the ones that worked or not...

Well I'm in Cal now so w/e lol.

Anyways thanks for helping him out Lev the math noob.

Lev's answer is so complicated. xD
|x| is greater than or equal to 2 is a million times easier to read.

OMG please never remind me of this horrible class

jj16802 wrote:OMG please never remind me of this horrible class

bad day in math for you as well?

Couldn't get some of the problems, just like I did in 9th grade. It's the recipe for disaster.

Ask the teacher?

Ahmed IV wrote:Ask the teacher?

the teacher is useless lol.

Go to another math teacher.

Every math teacher I had in high schools makes more jokes than teach the actual stuff

^^^That's my orgo teacher.

reviving this, factor this completely so i can check myself

2x^2-18x-72

and

12x^3+2x-30x-5


also another inequality like before

|2x-7|<9

2(x-12)(x+3)

Did you write the second one correctly? Check it.

Inequality solution: 0 is less than or equal to x. x is less than or equal to 4.

it's right

So why didn't you write: 12x^3+-28x-5 ?