The cost of manufacturing x units of a certain commodity is given by

C(x) = square root (5x +1) +4 (the 4 is out of hte square root)

dollars, where 0 <= x <= 10.

Find the marginal cost when the level of production is at 7 and at 16 units. Does marginal cost increase or decrease with increasing production?

Can someone please please please help me for this. I have a calculus test tomorrow. Although it's not the best idea to cram the night before, it's the only option I have at this point. I don't really want to know the answer exactly, since I have the answers.. But i want to know the process and a step by step would be great so I could do future problems.

Thanks alot!