a.b,c are three vectors of which every pair is non collinear.If the vectors a+2b and b+3c are collinear with c and a respectively,then a+2b+6c=
a.b,c are three vectors of which every pair is non collinear.If the vectors a+2b and b+3c are collinear with c and a respectively,then a+2b+6c=