Q7 of 58 Page 83

Find the value of m, if the points (5, 1), ( - 2, - 3) and (8, 2m) are collinear.

Since, the points

A = (5, 1)


B = ( - 2 – 3)


C = (8, 2m) are collinear


Area of ∆ABC = 0


1/2 [x1 (y2 - y3 ) + x2 (y3 - y1 ) + x3 (y1 - y2 )]=0


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


1/2 ( - 15 – 10m – 4m + 2 + 32) = 0


1/2 ( - 14m + 19) = 0


m = 19/14


Hence, the value of m =


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