Hello, I am having difficulty with the text and am not sure which formulas I need to use to answer this question:

Free cash flow valuationYou are evaluating the potential purchase of a small business with no debt or preferred stock that is currently generating $42,500 of free cash flow (FCF0=$42,500). On the basis of a review of similar-risk invest-ment opportunities, you must earn an 18% rate of return on the proposed pur-chase. Because you are relatively uncertain about future cash flows, you decide to estimate the firm's value using several possible assumptions about the growth rate of cash flows.a. What is the firm's value if cash flows are expected to grow at an annual rate of 0% from now to infinity?b. What is the firm's value if cash flows are expected to grow at a constant annual rate of 7% from now to infinity?c. What is the firm's value if cash flows are expected to grow at an annual rate of 12% for the first 2 years, followed by a constant annual rate of 7% from year 3 to infinity?