Problem #1: Find x3x 2 9 3 dx B. The marginal cost for producing x units of a product is given by 0.003x 2 2 x 20 dollars per unit. If the cost to...

Here i need help on question #1. open the accach file and do #1. please do it following the step that i post.

1)  Problem A- Using substitution

a.  (0.5 points) Identify the u, and du/dx.  Explain WHY you chose the u you did.  No explanation, no points.

b.  (1 point)  Change the integral from one in terms of x to one in terms of u.  Be careful to use correct notation (don't drop the integral sign or the du).  Explain this process.  No explanation, no points.

c.  (0.5 points) Find the antiderivative of integral in b. Explain this process.  No explanation, no points.

d.  (0.5 points)  Put antiderivative back in terms of x and report solution to original problem.  Don't forget the + C!

2)  Problem B (2 points)  You MUST explain your process for this one.  Just showing your work is NOT enough.  Explain what you did and why at each step.  No explanation, no credit.