A gas is compressed from an initial volume of 0.42 m3 to a final volume of 0.12

Question:

A gas is compressed from an initial volume of 0.42 m3 to a final volume of 0.12 m3. During the quasi-equilibrium process, the pressure changes with volume according to the relation P = aV + b, where a = - 1200 kPa/m3 and b = 600 kPa. Calculate the work done during this process
(a) By plotting the process on a P-V diagram and finding the area under the process curve and
(b) By performing the necessary integrations.