Could someone please help with these problems?

Thanks

Problem 5 The force required to stretch a spring r meters from equilibrium is F = kr. (a) The work done when stretching a spring 0.3 meters from equilibrium is 450 Joules. Calculate the force required to stretch this spring to 0.2 meters from equilibrium. Answer (simplify), with units: (b) It takes 300 Joules of work to stretch a spring 0.2 meters from equilibrium. Calculate the work done in stretching this spring an additional 0.3 meters. Answer (simplify), with units