Kindly show how you got it please

You have a light spring which obeys Hooke's law. This spring stretches 3.28 cm vertically when a 2.40 kg object is suspended from it. Determine the following. (a) the force constant of the spring (in N/m) N/m the distance (in cm) the spring stretches if you replace the 2.40 kg object with a 1.20 kg object cm (c) . the amount of work (in ]) an external agent must do to stretch the spring 7.10 cm from its unstretched position Additional Materials Reading