2.2. The following equations represent systems with input r(r) and output x(1). Compute the transfer func- x(1) tion, T(D)= r(t)' , for each system. Present your results in monic form using D operator notation. a. 3x(t) + x(t) = 2r(t) b. x(t) + x(t)=7ŕ(t) C. 2x(r) x(T) x(7)dr = r(t) d. 4x(t) + 7x(t)x(t) = 4ŕ(t) + 1(t)