Calculate the work done upon expansion of 1mol of gas

Question

(a) Calculate the work done upon expansion of 1mol of gas quasi-statically and isothermally from volume Vi to a volume vf, when the equation of state is

(P + (a/v²))(v-b) = RT,

Where a and b are the van der Waals constants.

(b) If a = 1.4 x 10⁹ N . m⁴ /mol and b = 3.2 X 10^-5 m³/mol, how much work is done when the gas expands from a volume of 10 liters to a volume of 22.4 liters at 20°C?