# Thread: Rearranging my perfect formula

1. ## Rearranging my perfect formula

Yes I am a student, and a newby, please be gentle with me . I am looking for help rearranging this formula I devised for a project (yes it is correct). Manipulation is not my thing so if anyone can crack it I would appreciate time and workings, I am sure this is easy for most people with an interest in math / physics.

Here goes- (((F/R)-m)/6)R=M, I need to make R the subject but I cannot figure out how to get the middle R out.

Happy figuring

Cheers
T

2. Originally Posted by horcigirl
... Manipulation is not my thing ...

Here goes- (((F/R)-m)/6)R=M, I need to make R the subject but I cannot figure out how to get the middle R out.

...
I'm going to show you what to do and maybe rearranging will become your favourite hobby:

$\displaystyle \dfrac{\frac FR - m}6 \cdot R = M$

$\displaystyle \left(\frac FR - m \right) \cdot R =6 M$

$\displaystyle F - mR =6 M$

$\displaystyle - mR =6 M - F$

$\displaystyle R =\dfrac{6 M - F}{-m} = \dfrac{F-6M}m$

3. ## Thats great and it works but!!

Awesome, That is sooo cool , I have checked it and it works but I am confused about some of your workings. Yes I am fascinated by how manipulation works but get confused by some issues. I had the right idea but I still cannot understand what happened to the middle R as it has just disappeared, I thought it would affect the other R to become R squared or 2R somehow. Why has it just been dropped?

I appreciate your help as I get very frustrated with this sort of thing, especially when I have been so clever with creating an effective formula lol.
Cheers
T

4. Originally Posted by horcigirl
I had the right idea but I still cannot understand what happened to the middle R as it has just disappeared, I thought it would affect the other R to become R squared or 2R somehow. Why has it just been dropped?
It has not disappeared, it has been distributed

$\displaystyle (a+b) \cdot c = a \cdot c + b \cdot c$

$\displaystyle \left(\frac FR - m \right) \cdot R =6 M$

$\displaystyle \frac FR \cdot R - m \cdot R =6 M$

$\displaystyle F - mR =6 M$

5. ## Understood

Thanks for the help. Its like multipliyng 1/2 by 2. I thought in this case both numerator and denominator would have had to be multiplied, still leaving FR. However I now understand what has been done.

Thanks to both advisors. My confidence is renewed. I see an A+ in sight lol.

Cheers
T