Final answer:
The question involves complex financial calculations for determining market value and expected equity return. However, insufficient data prevents from accurately performing these calculations.
Step-by-step explanation:
The question is about calculating the market value of a corporation before and after a repurchase announcement, and determining the expected returns on equity before and after this announcement, as well as for a hypothetical all-equity firm. To address part a, we need to calculate the market value of the firm using its EBIT and the cost of debt. However, the provided reference does not offer enough data to perform this calculation. Similarly, parts b, c, and d require additional information, such as the current market value of equity and details on the stock repurchase plan.
Without further information, we cannot accurately perform these calculations. It is crucial to have all necessary financial details to provide a precise answer especially when dealing with complex financial models like the Modigliani-Miller propositions.