Question

Rearrange for T and J;
n=(2J+1)exp(-(BJ(J+1))/(KT))
where B and K are constants

Answer 1

Here's how you would do it for T.

ln n = ln (2J+1) -BJ(J+1)/kT

ln [n/(2J+1)] = -BJ(J+1)/kT

kT = -BJ(J+1)/ln[n/(2J+1)]
Now divide both sides by k

Work similarly to solve for J

Answer 2

I understand how you do it for T, but since there is more than one J, I don't understand how you make J the subject.