(b) By using the method of completing the square, find the inverse Laplace transform of the function 4s-2 s2-6s+18 (c) A certain input-output system is shown in Figure 1. Input X(s) System Transfer Function Output 2 Y(s) H(s)=- (s+2)(s-1) Figure 1 (5 Marks) Is the system stable? Justify your answer. Hence, determine the system output y(t) if the input x(t) is a unit step function. (10 Marks)