So, how do we define temperature? Pressure?

Extensive parameters are given with the problem, but these Intensive parameters have a much deeper meaning that gives truth to the reasoning of why we separate between extensive and intensive parameters. So, without further ado:

T = (∂U/∂S)_V,N

P = -(∂U/∂V)_S,N

μ = (∂U/∂N)_S,V