Question

Find the value of $k,$ for which the points $(7,-2),(5,1)$ and $(3,k)$ are collinear.

Answer 1

If the given 3 points are collinear then the slope of any two points taken will be same.

Hence,

$\frac{1-(-2)}{5-7}=\frac{k-1}{3-5}$

$\frac{-3}{2}=\frac{k-1}{-2}$

$k=4$