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# Algebra with fractions Tweet

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1. Algebra with fractions
I have to find out what n equals for the equation below:

I'm confused on how I start off. This is mainly because of n being the the denominator.
2. Re: Algebra with fractions
Think about what would happen if you were to multiply both sides by something?
3. Re: Algebra with fractions
Do you mean by 6n as it's the LCM of 3n and 2n? or by just 6?
4. Re: Algebra with fractions
(Original post by krisshP)
I have to find out what n equals for the equation below:

I'm confused on how I start off. This is mainly because of n being the the denominator.
You need to put it all over a common denominator e.g. 6n like you suggested it can't just be six a 'n' is also a common factor between the two. LCM is exactly right
5. Re: Algebra with fractions
(Original post by books28)
You need to put it all over a common denominator e.g. 6n like you suggested it can't just be six a 'n' is also a common factor between the two. LCM is exactly right
Okay. I understand why I have to make 6n be the denominator. But how do I do that. The fact that the 2n and 3n are the denominators puts me off and makes it all hard for me.
6. Re: Algebra with fractions

Does that help?
7. Re: Algebra with fractions
Sophie's suggestion is easier by the way!
8. Re: Algebra with fractions
I think I worked it out but I'm not sure:

I multiply both sides by 3n, giving the following:

I minus 1 from both sides to give the following:

the Ns on the faction cancel out to give:

This causes in a different form:

Adding 1 to both sides provides:

Then dividing both sides by 21 to get n on its own gives:

Is this a right method or not?
9. Re: Algebra with fractions
1/2n+1/3n=7
1/2*1/n+1/3*1/n=7
(1/2+1/3)*1/n=7
You finish it off.
Last edited by WarriorInAWig; 15-04-2012 at 11:18. Reason: Latex is a pain
10. Re: Algebra with fractions
(Original post by krisshP)
Then dividing both sides by 21 to get n on its own gives:

Is this a right method or not?
Yes but horribly long winded. Can you use fractions rather than decimals?

Easier would be just to multiply by 6n.
11. Re: Algebra with fractions
Thanks!
12. Re: Algebra with fractions
(Original post by krisshP)
Thanks!
Have you ever seen a fraction that looks like that?
13. Re: Algebra with fractions
(Original post by krisshP)
Thanks!
It's 5/42.
14. Re: Algebra with fractions
I know. sorry. My clumsy mistake