Question

Find the value of $x$ if the points $(x,5),(2,3)$ and $(-2,-11)$ are collinear.

Answer 1

Points are collinear , so slope is equal $\left[\frac{y_2-y_1}{x_2-x_1}\right]=slope.$

$\frac{3-5}{2-x}=\frac{-11-3}{-2-2}$

$\frac{-2}{2-x}=\frac{14}{4}\Rightarrow -8=28-14x$

$14x=36\Rightarrow x=\frac{18}{7}$