A spring on a horizontal surface can be stretched and held 0.5 m from its equilibrium position with a force of 65 N. a. How much work is done in stretching the spring 2.5 m from its equilibrium position? b. How much work is done in compressing the spring 3.5 m from its equilibrium position? a. Set up the integral that gives the work done in stretching the spring 2.5 m from its equilibrium position. Use increasing limits of integration. dx (Type exact answers.)