Geo2.7

Find the equation of the straight line passing through the points $(1,1),(2,3)\,$

The equation of the straight line passing through two points is

$y-y_1=m(x-x_1)\,$ where m is a slope.

$y-1=\frac{3-1}{2-1}(x-1)\,$

$y-1=2x-2\,$

$y-2x+1=0\,$

The equation of the straight line is y-2x+1=0.