For the given cost function

C(x)=52900+200x+x2 find:

a) The cost at the production level 1000 = $1252900

b) The average cost at the production level 1000 = $1252.9

c) The marginal cost at the production level 1000 = $2201

d) The production level that will minimize the average cost?

e) The minimal average cost?

I know you have to divide c(x) by x units, then take the derivative... but it's just not working out for me.