Help - Problem with a simple Mathcad solution

Hello PTC community

I am in desperate need of a hand to solve an apparently simple thermodynamics problem.

I was able to get Mathcad to run my equations, but I am guessing I made a notation-related mistake somewhere in the file, and now I just can't figure out where! I've been going through all of it for hours, but with no success. I would be most glad if one could help me out here.

The thing is:

- The answer for Part A is correct. Part B and Part C aren't (in spite of being plausible), I checked it in the book. The correct answers for these questions are

Part B:

X.1 = 0.035

x.2 = 0.19

x.3 = 0.775

P = 69.129

Part C:

x.1 = 0.109

x.2 = 0.345

x.3 = 0.546

y.1 = 0.391

y.2 = 0.426

y.3 = 0.183

v = 0.677

Thanks for the help!