Question

Find value of k if the points -2,5 and -5,-10and k,-13 are collinear

Answer 1

Sol:

A(-2,5)

B(-5,-10)

C(K,-13) are Collinear

=1/2(X1(Y2-Y3)+ X2(Y3-Y1)+X3(Y1-Y2)

1/2(-2(-10-(-13))+(-5)(-13-5)+K(5-(-10))

1/2(-2(-10+13))-5(-18)+k(5+10)

1/2(-2(+3))+90+k(15)

1/2(-6+90+15k)

1/2(84+15k)=0

84=15k

84/15=K

K=6