Note that there are two poles in the system. The common region of the entire system is inside the one of the poles. Therefore, the region of convergence is less than the unit circle. Therefore, the signal is left-sided. If it is greater than unit circuit, it is a right-sided signal. If it is between the poles, it is two-sided. Solution Note that there are two poles in the system. The common region of the entire system is inside the one of the poles. Therefore, the region of convergence is less than the unit circle. Therefore, the signal is left-sided. If it is greater than unit circuit, it is a right-sided signal. If it is between the poles, it is two-sided..