First create a Simulink model containing an LTI System block to plot the unit-step response of the

Question:

First create a Simulink model containing an LTI System block to plot the unit-step response of the following equation for k = 4. The initial conditions are zero.
5d3x/dt3 +3 d2x/dt2 + 7dx/dt + kxy = us(t)
Then create a script file to run the Simulink model. Use the file to experiment with the value of k to find the largest possible value of k such that the system remains stable.