Kirchhoff's voltage law - multi-loop circuits

2020 Phase-2 1 question

1. For the circuit given below (with EMFs $E_1,E_2,E_3$ and currents $i_1,i_2,i_3$, resistances $R_1,R_2$, nodes A, B, C, D, E, F), the Kirchoff's loop rule for the loop BCDEB is given by the equation [add image]