The coefficient of x3 in x2+kx6is 360 then k is

General term Tr+1=6Crx26−rkxr=6Crx12−2rk2x−r=6Crkrx12−3rAccording to problem we need coefficient of x3 i.e.,  12−3r=3 9=3r ⇒r=3T3+1=6C3k3=360 (Given) 20k3=360k3=18k=183