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# How do I re-arrange these formulas watch

1. Make r subject

P = 2/3Mr^2

Make x subject

c = (ax+c)/(x-2)

these two are really making my mind boggle, on the second one I moved x-2 to the other side and got cx-2c = ax+c

then i added the 2 c and got

cx = ax+3c

is that even right? how do I get x from that =?
2. (Original post by TimetoSucceed)
Make r subject

P = 2/3Mr^2
For this one, start by making the subject, and then just take the square root of both sides.

(Original post by TimetoSucceed)
Make x subject

c = (ax+c)/(x-2)

these two are really making my mind boggle, on the second one I moved x-2 to the other side and got cx-2c = ax+c

then i added the 2 c and got

cx = ax+3c

is that even right? how do I get x from that =?
You're almost there, subtract from both sides (to take it over to the LHS) and then take out of the LHS as a common factor. Then there's something you can do to finish it off.
3. (Original post by TimetoSucceed)
Make r subject

P = 2/3Mr^2

Make x subject

c = (ax+c)/(x-2)

these two are really making my mind boggle, on the second one I moved x-2 to the other side and got cx-2c = ax+c

then i added the 2 c and got

cx = ax+3c

is that even right? how do I get x from that =?
For the first one, rearrange to get r^2 as the subject and square root.
For the second one, you're on the right track. When you have cx=ax+3c, move the ax to the other side, take a common factor of x out and divide by c+a.
4. thanks a lot =] makes sense now
5. (Original post by Gemini92)
For the first one, rearrange to get r^2 as the subject and square root.
For the second one, you're on the right track. When you have cx=ax+3c, move the ax to the other side, take a common factor of x out and divide by c+a.
dont you mean c-a?

x(c-a) = 3c so I divide 3c by c-a right? I get

x = 3c/(c-a)
6. (Original post by TimetoSucceed)
dont you mean c-a?

x(c-a) = 3c so I divide 3c by c-a right? I get

x = 3c/(c-a)
That's right, yup.
7. (Original post by TimetoSucceed)
dont you mean c-a?

x(c-a) = 3c so I divide 3c by c-a right? I get

x = 3c/(c-a)
Yes, I did mean c-a, sorry.

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