Question

Find the equations to the straight lines passing through the pairs of points. : $(0,0)$ and $(2,-2)$.

Answer 1

General equation of pair of points is

$y-y_1=\frac{y_2-y_1}{x_2-x_1}\times (x-x_1)$

$y-0=\frac{-2-0}{2-0}\times (x-0)$

$\Rightarrow y=-x$

Therefore required equation is $x+y=0$