Question

Find the equation of a line that goes through points (-3, -5) and (-1, -2).

Answer 1

The slope-point formula:

$y-y_1=m(x-x_1)$

The formula of a slope: $m=\dfrac{y_2-y_1}{x_2-x_1}$

We have:

$(-3,-5)\to x_1=-3,\ y_1=-5\\(-1,-2)\to x_2=-1,\ y_2=-2$

Substitute and calculate:

$m=\dfrac{-2-(-5)}{-1-(-3)}=\dfrac{3}{2}=1.5\\\\y-(-5)=1.5(x-(-3))\\\\y+5=1.5(x+3)\\\\y+5=1.5x+4.5\ \ \ |-5\\\\y=1.5x-0.5$