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#1 2010-10-14 18:36:12
- haftakhan
- Member
- Registered: 2010-06-28
- Posts: 30
Expansion and Factorisation of Algebraic Expressions
A. Factorise completely:
(a) 18x^2 24xy + 8y^2
the answer i get is 2(3x+y)^2
but the answer given is 2(3x + 2y)^2
B.Factorise the following:
(a) (x 4)(x + 1) + 4a ax
the answer i get is (x-4)(x+1-a)
but the answer given is (x-4)(x-1-a)
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#2 2010-10-14 18:46:03
- bobbym
- bumpkin
- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606
Re: Expansion and Factorisation of Algebraic Expressions
Hi;
(a) 18x^2 24xy + 8y^2
the answer i get is 2(3x+y)^2
but the answer given is 2(3x + 2y)^2
For A) Both answers are incorrect!
(a) (x 4)(x + 1) + 4a ax
the answer i get is (x-4)(x+1-a)
but the answer given is (x-4)(x-1-a)
For B) you are right and the given answer is wrong!
In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.
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#3 2010-10-14 22:23:26
- haftakhan
- Member
- Registered: 2010-06-28
- Posts: 30
Re: Expansion and Factorisation of Algebraic Expressions
18x^2 24xy + 8y^2
=2(9x^2-12xy+4y^2)
=2{(3x)^2-2(3x)(2y)+(2y)^2}
=2(3x-2y)^2
but the answer given is 2(3x + 2y)^2
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#4 2010-10-14 22:29:18
- bobbym
- bumpkin
- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606
Re: Expansion and Factorisation of Algebraic Expressions
Hi;
Now that is the right answer. The given answer is wrong there.
In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.
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#5 2010-10-14 22:34:57
- haftakhan
- Member
- Registered: 2010-06-28
- Posts: 30
Re: Expansion and Factorisation of Algebraic Expressions
Hi and thanks
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#6 2010-10-14 22:38:28
- bobbym
- bumpkin
- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606
Re: Expansion and Factorisation of Algebraic Expressions
Good work by the way!
In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.
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