1) If a,b and c are three non-collinear points and ka+2b+3c is a point in the plane of a,b, c then k= A) 4 B) 5 C) -5 D) -4 Answer: Option CExplanation:a,b, and c are three non-collinear point and ka+2b+3c is a point in the plane a,b, c $\therefore$ ka+2b+3c=0 $\Rightarrow$ k+2+3=0 $\Rightarrow$ k=-5
