Dear  Hexin,

 Please consult

https://sites.math.rutgers.edu/~zeilberg/Hist21/mt2S.pdf

for the full solutions.


You got  99 points (out of 120)


Here is what you got wrong:

#4(c)(d): -6 points

#5: -10 points


#9: -5 points


 Best wishes,

   Dr. Z.