Problem on ideal elastic substance

Question

Solve the following problem:

1. The equation of state of an ideal elastic substance is

ζ = KT (L/L₀ - L²₀/L²)

Where K is a constant and Ls (the value of L at zero tension) is a function of temperature only. Calculate the work necessary to compress the substance from L = L₀ to L = L_o/2 quasi-statically and isothermally.

2. Show that the work required to blow a spherical soap bubble of radius r in an isothermal, quasi-static process in the atmosphere is equal to 8πγr².