Question

Find the value of m if the points A (5,1), B(-2,-3) and C(8,2m) are collinear
m= _
(Enter in the form a/b if you obtain a fraction)

Answer 1

If A (5,1), B(-2,-3) and C(8,2m) are collinear, then the area of the triangle formed by A, B and C is zero.

Thus, 1/2 x [5(-3-2m)+(-2)(2m-1)+(8(1-(-3))] = 0

Or, [5(-3-2m)+(-2)(2m-1)+(8(1-(-3))] = 0

[-15 -10m-4m +2+32] = 0

-14m+19 = 0

m = 19/14.