GREs - the shame!

Sissyfoo

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In order to do my masters in the good ol' US of A, I need to do this damn exam called a GRE (Graduate Record Examination). Normally I wouldn't be too bothered about something like this but there is a math section which is full of weird equations like:

Code:
Factor completely : 2x³ + 8x² - 90x
AUUUGH!! I haven't done anything like this since my GCSEs! I can't even remember what teh fuck 'factor' means!! :mad:

I'm gonna have to dig up my school books from almost 10 years ago and try to decipher them. I am not a happy bunny.

The other half of the test is basically a vocab thingy. Looks like most of it is pretty easy but they seem to enjoy using certain words which are practically obsolete in the english language. Whores. :mad:

Can't they just, like, umm, read this forum and give me a masters based on my posts? So unfair.
 

Brynn

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is that X to the power s or 3? coz if its 3 i can help :p
 

Brynn

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use the (-b+-(thats plus or minus) ((root)( b²-4ac))) ALL OVER 2a

a = 2
b = 8
c = -90
 

Sissyfoo

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Ooo eck. Its not like I need to know this stuff for my degree anyhow. :(

I hope my math books aren't full of doodles of super powered hamsters (I seem to recall I was obsessed with radioactive rodents when I was young) and actually have something useful in them. :)
 

Brynn

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..i worry about you :p


how old are you btw anyway?
 

Sissyfoo

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24-ish! Mouldy Oldy!

I'm gonna be getting around in a freakin' zimmerframe by the time I am done in Uni. :-o
 

Brynn

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5 years older than me :eek2: old fart :p


i hate pl-ing in barrows. so boring no one from my guild is on aaargh.


I hate maths too, had a maths test 2day. Think i passed (read...hope i passed)
 

Sissyfoo

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I don't hate maths as such. I don't remember enough of it to warrant any hatred. :mad:
 

Brynn

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I need it for my course, which sucks balls.

/and before some mods say take it to IRC - well i cant sissy doesnt have irc/or an ability to get it, and i would like to catch up with my friend Sissy (who i haven't spoken to in a while)
 

Sharma

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Er i thought:
2x³ + 8x² - 90x
Would go to:

10x^5 - 90x

So 80x^5 or something :x

I dont think you can use a quadratic equation to figure it out since it doesnt = 0
 

BlitheringIdiot

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Right basically factorise means break it down into its smallest components, generally when you see 'factorise' it means put it in brackets.

First step is to shove an X outside as they are all factors of x.

This leaves you x(2x2 + 8x - 90).

Then its just a regular quadratic, which can be factorised with a relative degree of logic.

Anyway the final answer is:

x(2x-10)(x+9)
 

BlitheringIdiot

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Sharma said:
Er i thought:
2x³ + 8x² - 90x
Would go to:

10x^5 - 90x

So 80x^5 or something :x
You cannot add the powers when adding the x's. You add thme when multiplying the x's. Proof: let x=3, 3x3+3x3x3=36 3x3x3x3x3=243.

Also Brynns way would only work if you took out a factor of x (ie 2x2+8x+90), then applied the equation. However that equation is merely a way of employing the completeing the square thing, I personally think it just makes it more complicated than it actually is. Plus its actually useless as the question doesnt ask for the values of x, it asks for the equation to be broken down. I suppose you could work out the brackets from the values but that would be near impossible, and only doable by trial and error.
 

BlitheringIdiot

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BlitheringIdiot said:
x(2x-10)(x+9)
If it also asks for values of x, then (presuming its equal to zero):

x(2x-10)(x+9)=0

therefore:

x=0 or x = 5 or x =-9

(ie if you replace ever 'x' wit hone of those three numbers then the answer will always come out as zero, this will work with no other numbers)
 

BlitheringIdiot

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Oh and yes, that is GCSE maths :p

(and yes I do know where the edit button is, but I'm too intelligent for that)

If you have any other mathsy type questions unexpectadly appear, give me a PM. I actually enjoy them... :eek:
 

'Shy

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Wtf??? Never did any of that bollocks when I was at school! *tut* kids of today...
 

BlitheringIdiot

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[QUOTE='Shy]Wtf??? Never did any of that bollocks when I was at school! *tut* kids of today...[/QUOTE]
If you did GCSE Maths then you did factorise quadratics, in fact in your day you were often not allowed to use the forumla that brynn posted. So ner :p
 

yaruar

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BlitheringIdiot said:
If you did GCSE Maths then you did factorise quadratics, in fact in your day you were often not allowed to use the forumla that brynn posted. So ner :p
I was too stoned to remember any of my gcse maths, let alone my a-level maths.. I really should reteach myself at some point as all that seemed like gibberish.

It's even more embarrssing as my degree involved some pretty advanced maths for the stats and econometric side of things..

doh.
 

Chilly

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well yer fuct if u cant factorise a simple cubic, quadratics are generally work out in head jobbies unless theyr gay and have arsey numbers that ar too long for their own good. I happen to need maths quite centrally for my degree so cubics are a tad simple ;)
If you need to solve any 2nd order differential equation Sissy im yerman!
 

BlitheringIdiot

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yaruar said:
It's even more embarrssing as my degree involved some pretty advanced maths for the stats and econometric side of things..
STATS IS NOT PROPER MATHS!!11 :twak:
 

Brynn

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Chilly said:
If you need to solve any 2nd order differential equation Sissy im yerman!
If you need any Linear Ordinary Differencial Equation solved come to me :p
 

BlitheringIdiot

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Brynn said:
If you need any Linear Ordinary Differencial Equation solved come to me :p
2x-1=5
Think you can handle it? :p (considering you'd have failed miserably at that relatively straight forward question sissy posted...)
 

Brynn

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well the questions i have been doing, you are unable to break it down easily you have to use the formula i said :p So im using that formula as my 1st thought when i see those questions.

2x-1 = 5
2x = 6
x = 3
 

BlitheringIdiot

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Brynn said:
well the questions i have been doing, you are unable to break it down easily you have to use the formula i said :p So im using that formula as my 1st thought when i see those questions.
Except for the fact that the formula gives you the values for x IF the equation is equal to zero, you dont know that the equation is equal to zero as it doesnt state it, it also doesnt even ask for the values of x, it asks for the equation to be factorised! :p
 

Brynn

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.... oh look, urm someone is at the door :p

oh bugger, if it means it has to be equal to zero that means i have fucked up a question in my test :(
 

BlitheringIdiot

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Brynn said:
.... oh look, urm someone is at the door :p

oh bugger, if it means it has to be equal to zero that means i have fucked up a question in my test :(
If its not equal to zero then you have to make it equal to zero to apply the equation.

say you had:

x2+7x+8=x-1

You'd HAVE to re-arrange it before applying it to the quadratic equation:

x2+6x+9=0

Then plug the numbers in, in this case the answer would be:

x= -3

By the way if you arent sure of your answer, shove whatever value(s) you got back into the equation and see if it works:

x2+7x+8=x-1
(-3)2 +7(-3) +8 = (-3) - 1
9 - 21 + 8 = -3 -1
-4 = -4


So it works! :)

EDIT: I like the avatar by the way, very nice ;)
 

Brynn

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Lets just hope i get the marks for the working :(

God bless maths you can get 9/10 marks even tho you got the wrong answer :D


Hehe thanks Blith. Took me all of 5 mins to cobble together
 

Sissyfoo

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Don't take this personally guys but I don't think I will be taking maths lessons from you seeing as you are all posting different solutions. :p I'll just pick up me trusty ol' math book (the doodle free variety) and plug away at it for a few months. I used to be pretty good at all that quadratic malarky but then I erased it from my mind after GCSEs. :mad:

Good thing I won't need to know any of this crap again after I have taken the test. ...just lots and lots of stats. ~cries~
 

'Shy

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BlitheringIdiot said:
If you did GCSE Maths then you did factorise quadratics, in fact in your day you were often not allowed to use the forumla that brynn posted. So ner :p
Nah I never paid attention, never tried, and got an E :D
 

Sissyfoo

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How can you be in sales and have an E in maths? :p
 

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