Question

Find the value of k, if the following three points are collinear (-2,-5), (-3,-k), and (-5,1).​

Answer 1

Answer:

given, the points are collinear

hence area of triangle formed by these three points must be zero.

|. -2. -5. 1. |

1/2 | -3. -k. 1 | = 0

|. -5. 1. 1 |

-2(-k - 1) - (-5)(-3-(-5)) + 1(-3-5k) = 0

2k + 2 - 15 + 25 - 3 - 5k = 0

5k - 2k = 25+2-15-3

3k = 9

k = 3