Question

Find the equation for the line through points (0,-1) and (-3,0) use y=Mx+b

Answer 1

first we must find the slope, the formula is

$m=\frac{y_2-y_1}{x_2-x_1}$

using the values x1=0, y1=-1, x2=-3, y2=0

$m=\frac{0-(-1)}{-3-0}=-\frac{1}{3}$

then we use the equation

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

and using the values

$\begin{gathered} y+1=\frac{-1}{3}(x-0) \\ y+1=-\frac{1}{3}x \end{gathered}$

organizing the equation

$y=-\frac{1}{3}x-1$

and this is the equation of the line.