a) [15points] use your own words to explain (in less than 40 words) what kind of information the Routh's stability criterion tell us about the system? What is the meaning of the appearance of an entire row of zeros in the Routh's table?Provide an example to support your answer. b) [15points] use your own words to explain (in less than 40 words) what is the performance specifications of the first-order system, and what is the information provided by the specification for a first-order system.For second-order systems, if a pole of a system A is mo ved while keeping the imaginary part constant to create system B, what will the responses of systems A and B have in common? Provide an example.