Answer
a) Gordon's Constant Growth model : P0 = D1 / (r-g)
r = 3% =0.03
, g= -7% = -0.07
, D0 = $5.1
D1 = D0*(1+g)
D1 = 5.1*(1-0.07)
D1 = $4.743
P0 = 4.743/(0.03- (-0.07))
P0 = 4.743/0.10
P0 = $47.43
So, Stock M should sell at a price of $47.43 today
b) Price 8 years from now
==> P8 = D9/(r-g)
P8 = D0*(1+g)^9/(r-g)
P8 = 5.1* (1-0.07)^9 / (0.03- (-0.07))
P8 = 5.1*0.52041108298 / (0.03- (-0.07))
P8 = 2.65410
P8 = $26.54
c) Investor may want to buy the stock today for the Dividends. If the dividends paid are high enough, the present value of the dividends is also high and may more than compensate the fall in stock price. This type of stocks work and give cash flows like a project where the initial cashflows are higher and later cashflows are less because of market factors.