Donate SIGN UP

Maths question

Avatar Image
jimzee4 | 20:20 Thu 10th Jun 2010 | Science
10 Answers
Factorise a^2(b-c)+b^2(c-a)+c^2(a-b)
^2 means squared
Any ideas?
Gravatar

Answers

1 to 10 of 10rss feed

Avatar Image
^2(b-c)+b^2(c-a)+c^2(a-b)=a^2(b-c)+bc(b-c)-a(
b^2-c^2)

Since b^2-c^2=(b+c)(b-c) this becomes
a^2(b-c)+bc(b-c)-a(b+c)(b-c)
=(b-c){a^2+bc-a(b+c)}
=(b-c){a^2-ab+bc-ac}
Rearranging the stuff in the curly brackets to get a common factor of (a-c) gives
(b-c){a(a-c)-b(a-c)}
=(b-c)(a-c)(a-b)
07:16 Fri 11th Jun 2010
Into what form? It has already been factorised in a way, but you can reorganis eit and factorise it in another way.
First expand all the brackets

= a²b - a²c+ b²c-b²a +c²a-c²b
= a²b -b²a +c²a - a²c+ b²c -c²b
= ab(a-b) +ac(c-a) + bc (b-c)

I'm not sure this is any better though than the original expression.

Are you sure you've stated the question exactly?
If you mean factorise so it's all in brackets then you can do this (but I can't type out each line, take too long):
Multiply out first to get
a^2b - a^2c + b^2c - b^2a + c^2a - c^2b
You can then rearrange the order and get terms and take (b-c) as a factor (not doing it all for you) to give an answer of:

(b-c)(bc + a^2 - ac - ab)
How do you do the squared symbol factor, found using that ^ very confusing?
Yes I suppose you could take other combinations of Prudie's solution as well- eg take a-b as a factor.
However I think you can make 3 brackets.
I've not got time to work it out but if you juggle around with + and - signs you can try variations of (a-b)(a-c)(b-c). In fact that may be the answer
Prudie- to get the ² sign I simply type it in Word then paste it into AB
If you type it into Google, you'll get the answer.
Can you show us that, woody?
Regards
^2(b-c)+b^2(c-a)+c^2(a-b)=a^2(b-c)+bc(b-c)-a(
b^2-c^2)

Since b^2-c^2=(b+c)(b-c) this becomes
a^2(b-c)+bc(b-c)-a(b+c)(b-c)
=(b-c){a^2+bc-a(b+c)}
=(b-c){a^2-ab+bc-ac}
Rearranging the stuff in the curly brackets to get a common factor of (a-c) gives
(b-c){a(a-c)-b(a-c)}
=(b-c)(a-c)(a-b)
Sorry that first line should be:
a^2(b-c)+b^2(c-a)+c^2(a-b)=a^2(b-c)+bc(b-c)-a
(b^2-c^2)
Question Author
Thanks everybody. Only just saw the answers.
Too much footie.Will get back to the maths.

1 to 10 of 10rss feed

Do you know the answer?

Maths question

Answer Question >>