This is what I would do, first reform:
Substitute (1) in (2) and rewrite it as
Hi, I have the following problem:
The pressure, p, and volume, V, of a gas undergoing a polytropic process are related by the equation
p1V1^n = p2 V2^n
where n is the polytropic index.
If (p1V1)/T1 = (p2V2)/T2
determine an expression for p1, in terms of p2, T1, T2 and n.
(1 and 2 should be lower case) formatting didn't quite work!...
Thanks for the help. So after substitution p1 = (p2.T1)/T2 x nthroot(p1/p2)
I'm still not sure how I go about rearranging to get rid of the nthroot(p1) term on the right hand side though, as ideally we just want p1 = .... without another p1 term in the equation, if you know what I mean?