The combines law of gas is:
P1 * V1 P2 * V2
---------- = -----------
T1 T2
So, you can obtain many equivalent valid forms depending on the variable that you solve for.
These are some examples:
Solve for T1:
T1 = T2 * (P1 * V1) / (P2 * V2)
Solve for V2:
V2 = V1 * (T2 / T1) * (P1 / P2)
Solve for P1:
P1 = P2 * (T1 / T2) * ( V2 / V1)