Yes, as long as the two are not mutual resiprocals.
NOT Possible. In a parallel combination the power tollerence has to increase, thus for every additional resistor in parallel the effective power capacity of the resister would be n(12) Watts where n is the number of resistors connected. ie. if n=3 the power of the combination would rise to 12 x 3 = 36W. Also it is not possible to compute the effective resistance of the combination unless the resitance value of the resitors utilised is known. The question is therefore invalid.