its not that hard. You don't even have to find out if it's productive or not. That's really just a remedial step.I'm not mistaken, I think you just need to do this for b

b)

|0.1 0.2 0.05| |10|

|0.25 0.45 0.10| |15|

|0.35 0.15 0.15| * |20|

(multiply your consumption matrix by the vector 10,15,20)

c) I'm not sure, I'll have to look at my notes. I'm also taking this class right now

d)

subtract from the identity matrix

|1 0 0|

|0 1 0| - |your consumption matrix|

|0 0 1|

then augment your new matrix with 30,50 and 40 in the last column

after that, just put the matirx in reduced row echelon form, that will give you the gross production for x,y and z.