The equivalent annual annuity (EAA) method is useful in determining O which one of two machines should be purchased when the machines are mutually exclusive, have different lives, and will be replaced once they are worn out which one of two investments to accept when the investments have different required rates of return which one of two machines should be purchased if the machines are mutually exclusive, have the same lives, and are a one-time purchase o the tax shield benefits of depreciation given the purchase of new machines for a product line