Please help with one or both if possible. Thank you!

VALUATION OF A DECLINING GROWTH STOCK Martell Mining Company's ore reserves are being depleted, so its sales are falling. Also, because its pit is getting deeper each year, its costs are rising. As a result, the company's earnings and dividends are declining at the constant rate of 5% per year. If D_0 = 85 and r_s = 15%, what is the value of Martell Mining's stock? VALUATION A CONSTANT GROWTH STOCK A stock is expected to pay a dividend of $0.50 at the end of the year (that is, D_1 = 0.50), and it should continue to grow at a constant rate of 7% year. If its required return is 12%, what is the stock's expected price 4 years from today? VALUATION OF A CONSTANT GROWTH STOCK Investors require a 15% rate of return on Levine Company's stock (that is, r_s = 15%). a. What is its value if the previous dividend was D_0 = $2 and investors expect dividends to grow at a constant annual rate of (1) -5%, (2) 0%, (3) 5%, or (4) 10% b. Using data from Part a, what would the Gordon (constant growth) model value be if the required rate of return was 15% and the expected growth rate v (1) 15% or (2) 20%? Are these reasonable results? Explain. c. Is it reasonable to think that a constant growth stock could have g > r_s? Why or why not