1. The problem statement, all variables and given/known data Determine the closed loop transfer functions of the systems shown below: 2. Relevant equations Standard block diagram algebra. 3. The attempt at a solution I've moved the take off point such that the diagram now looks like: I am having difficulty determining G1(s). The solution given is G1(s) = 4(s + 2) + 1 = 4s + 9 But it is not obvious to me where this is coming from. Taking G1(s) as given, I am able to solve the rest of the question without issue. Any help appreciated.