The problem statement: I have to find the transfer function of a mass spring system. There are two masses in the system and 3 spring. I also have to find the state space representation and the model of the system. I have attached a image of my problem and my work so far. I think I found the model of the system but I'm stuck at the transfer function part. I have two system equations, one for each mass. I'm not sure how I can combine them and get one transfer function. The attempt at a solution: Please see the attached file. Sorry, I didn't want to type the problem and my solution.