For the system s + 3 / s² + 4s + 5 , what value of gain will make the closed loop system critically damped?

For the system 1 / s² + 6s + 5 , how many infinite zeros are there?

For the system s² + 9 / s³ + 1s² + 6s + 5 , how many finite zeros are there?

For the system s - 1 / s³ + 1s² + 6s + 5 , how many poles are there?

For the system s - 1 / s³ + 1s² + 6s + 5 , what is the value of the pole closest to the j? axis?