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# Algebra with fractions Watch

1. 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. Think about what would happen if you were to multiply both sides by something?
3. Do you mean by 6n as it's the LCM of 3n and 2n? or by just 6?
4. (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. (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. Does that help?
7. Sophie's suggestion is easier by the way!
8. 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. 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.
10. (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.
Thanks!
12. (Original post by krisshP)
Thanks!
Have you ever seen a fraction that looks like that?
13. (Original post by krisshP)
Thanks!
It's 5/42.
14. I know. sorry. My clumsy mistake

Updated: April 15, 2012
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