Decide whether the matrices in Exercises 1 through 15 are invertible. If they are, find the inverse. Do the computations with paper and pencil. Show all your work.

L21 - 7 An Economics Example The price of a product is related to the number of items that will sell. We consider the demand function p(x) where p is the price per unit at which the company will sell x units. This is expected to be a decreasing function. Total revenue from the sale of x items is then R(x)= xp(x). ex. Suppose that the demand function for a product is x p(x)=50 − ,0 ≤ x ≤ 10,000. 200 If revenue is increasing at the rate of $2400 per week, at what rate is the production level x changing with respect to time if the current weekly production level is 200 units