how to solve?

2. Figure 2 depicts three masses, m1, ma, and my connected by springs. The springs on either end are connected to walls. YOU MAY ASSUME ki - k2 = 3 = k4 and that all the masses are the same. a) (20 points) Find the equations of motion for this system. b) (30 points Find the normal mode frequencies, @ for this system. c) (10 points) Can you identify what motion the three eigenvectors identify in the system