If →r=3^i+2^j−5^k, →a=2^i−^j+^k, →b=^i+3^j−2^k and →c=−2^i+^j−3^k such that →r=l→a+m→b+n→c, then
If →r×→b=→c×→b and →r.→a=0 where →a=2^i+3^j−^k,→b=3^i−^j+^k and →c=^i+^j+3^k, then →r is equal to