For the given cost function
C(x)=40000+800x+x2\displaystyle {C}{\left({x}\right)}={40000}+{800}{x}+{x}^{{2}} find:
a) The cost at the production level 1150  
b) The average cost at the production level 1150  
c) The marginal cost at the production level 1150  
d) The production level that will minimize the average cost  
e) The minimal average cost