How do I find the power factor and the equivalent inductivity value for this given scheme?
I'm not sure the real question is what you think it is. From the sentence "find out the equivalent value of inductivity" I think you have to handle this dipole as a series R-L with impedance of 40+j7 ohms. 

What values of R and L in series can have this impedance? Well R have to be 40ohm and L has to be...this was the real question I think. The answer is easy, if 
X= ω*L, then L=X/ω
Since you didn't gave us the frequency, I cant substitute for ω (ω=2*п*f), but I think you can handle this.

Your other question is almost solved by you. Yes you can replace those values, so kp = R/|Z|, where |Z| is the absolute value of the impedance you calculated, so |Z|=sqrt(R^2 + X^2)