Find the value of 'p' for which the points (-1,3) , (2,p) and (5,-1) are collinear.
there is an easier method,,,
if the lines r collinear they cannot be vertices of a triangle
so.. Ar. of triangle = 1/2 [ X1 (Y2-Y3) + X2 (Y3-Y1) + X3 (Y1-Y2) ]
since ar. of triangle should be 0
0 = 1/2 [ X1 (Y2-Y3) + X2 (Y3-Y1) + X3 (Y1-Y2) ]
substitute the values nd u will get the answer !!!
Hope it helped :D