Question

Sol. (4) Here, ( x_{1}=-1, x_{2}=2, x_{3}=5, y_{1}=3, y_{2}=k )
and ( y_{3}=-1 )
since, points are collinear.
Area ( (Delta)=0 )
( x_{1}left(y_{2}-y_{3}right)+x_{2}left(y_{3}-y_{1}right)+x_{3}left(y_{1}-y_{2}right)=0 )
( -1(k+1)+2(-1-3)+5(3-k)=0 )
( -k-1-8+15-5 k-0 )
( 6 k=6 Rightarrow k=1 )

# Ez. 2. Find the value of k for which the points A(-1.3). B (2, k) and (5, -1) are collinear, (1) 2 (2) 4 (3) 5 (4) 1

Solution