# Equation of a Straight Line

The general equation of a straight line is given by: $y=mx+c$

Where $m$ is the slope, and $y=b$ the $y-intercept$ (where the line cuts the $y-axis$).

$m$ is given by,
$m=\frac{y_2-y_1}{x_2-x_1}$.
Hence,
$y-y_1=m(x_2-x_1)$
$y-y_1=\frac{y_2-y_1}{x_2-x_1}(x_2-x_1)$