HELLO,
YOU CAN USE THIS METHOD IN FINDING THE TOTAL RESISTANCE SEEN BY A VOLTAGE SOURCE.
1. AT THE TERMINALS OF THE VOLTAGE SOURCE NAME (a,b), THEN WHEN U FIND ANY RESISTANCE NAME ©, THEN GO ON d,e AND SO ON.
2. REDRAW THE CCT IN A NEAT FORM BY PUTTING THE LETTERS (a,b,c,d...) THEN SEE WHERE IS...