A challenging question (1 Viewer)

[munkie]

hey everyone!!!

Ive got this tricky question (probably way too easy for u maths gurus )

If a+b+c=0, show that (2a-b)^3 + (2b-c)^3 + (2c-a)^3 = 3(2a-b)(2b-c)(2c-a)

Could someone please show me how to do it, please???

Thanks in advance.

 

[QuaCk]

you're just gonna delete this after it gets answered eh?

 

[Slidey]

you're just gonna delete this after it gets answered eh?

And he/she will probably also make a new account.

 

[table for 1]

can we not get into that. once this person recieves the answer, there will no longer be a need for this thread, so s/he may do as s/he pleases

btw, i've forgotten how to expand cubics... -.-" hang on a long while, while i figure it out, or look it up. i think it's better if someone else answers instead

 

[table for 1]

hey slide rule ! i just realised that your username is bolded and in a diff font ! does this mean you've been promoted or something?

 

[Slidey]

Promoted? You could put it that way - I wouldn't.

I'm a Benefactor: http://boredofstudies.org/community/showthread.php?t=58291

 

[Trev]

can any1 answer the question? lol. i cant

 

[Trev]

And he/she will probably also make a new account.

why would they make a new account?

 

[table for 1]

Promoted? You could put it that way - I wouldn't.

I'm a Benefactor: http://boredofstudies.org/community/showthread.php?t=58291

mad.. !!



lol...i can't get it neither...i blame it on my crap algebra skills

 

[Trev]

haha i blame it on my stoopidity

 

[table for 1]

lol....dammit i refuse to give up trying until this question is solved....somebody solve it already and put me out of my misery....

 

[its_bui]

wot topic does this question go under?

 

[Trev]

algebra? eh

 

[Trev]

lol....dammit i refuse to give up trying until this question is solved....somebody solve it already and put me out of my misery....

hav u tried expanding the whole question? lol, i guess thatd work, but that wouldnt be the way its sposed to be done.........

 

[table for 1]

yeah, and i end up with this really long thing that i've half factorised, and i'm not even sure i'm doing it correctly - maybe i'm making my own factorising rules

 

[withoutaface]

munkie: This is quite annoying and it clogs up the forum (at least for me, about 90% of the first page appears as deleted threads:/ So can you just post all your questions in one thread and not delete it?

As for your question, expanding it should work, but for the life of me I can't think of how to do it otherwise:S

 

[Slidey]

As for your question, expanding it should work, but for the life of me I can't think of how to do it otherwise:S

Same... which sucks. I like elegance... expanding ain't elegant.

 

[table for 1]

argh !! this is annoying me. i'm seriously thinking that i'm making up my own factorising rules [ie. factorising wrongly] and that's why it's not working. can someone just do it and make me stop obsessing over this stupid question?

i bet you that someone's going to come along and get it right on the first go that it'll make me look really stupid for not having done it like that. this is so gay.

 

[QuaCk]

i think you can only expland like crazy
i havn't tried it yet
but can't see any other way

i'm hoping some bright spark can show me a sexy method.

 

[table for 1]

meh...i cbb doing it anymore. later...i'll face it afresh