A practical application of subtracting polynomials is finding the profit function P(x) for a business given the revenue function R(x) and the cost function C(x). Profit = Revenue - Cost
P(x) = R(x) - C(x)

3. The cost function for a company to produce armbands is C(x) = 2x + 5000, where x is the number of armbands. The company sells the armbands for $7 each. Write the revenue function and the profit function for the company.