We Know ∵OA+OB+OC+OD+OE+OF+OG+OH=0
By triangle law of vector addition, we can write AB=AO+OB;AC=AO+OC AD=AO+OD;AE=AO+OE AF=AO+OF;AG=AO+OG AH=AO+OH
Now AB+AC+AD+AE+AF+AG+AH =(7AO)+OB+OC+OD+OE+OF+OG+OH =(7AO)+0−OA =(7AO)+AO =8AO=8(2i^+3j^−4k^) =16i^+24j^−32k^