Please help answering all the questions? Thanks

a. Write down the equation of the Security Market Line. Explain this equation. Explain how "beta" is related to the concept of risk. b. Explain how to use the CAPM to estimate the companies cost of capital if there is no debt. c. How does your answer to b) change if the company borrows money. d. What is the beta of a portfolio with a large number of randomly selected stocks. Why? e. Explain how the CAPM is related to the assumption of market efficiency