At 18°C the total volume V of a solution formed from MgS04 and 1.000 kg of water fits the expression v = 1001.21 + 34.69(x - 0.070)2, where v = V/cm3 and x = blb-1. Calculate the partial molar volumes of the salt and the solvent when in a solution of molality 0.050 mol kg-1•