QUESTIONS $1.$ Find the transfer functions C$($$$)/$R$($s$)$ of the following system configurations: a$.$ by writing the equations and eliminating the variables. b$.$ using Mason's formula. R$(3)$ EX$)$ MG$)$ Cs$)$ GA$)6,18)$ HO$)($a$)$ GO$)$ RES$)$ MO$)$ C$($s$)66$ HU$)($b$)$ RS$)$ EN$)$ MG$)$ G $()$ CO H:$)$