Question

Find the equation of the line through (-8,-7) and (0,-9)

Answer 1

What is the formula for this equation?

Answer 2

If the equation of the line is linear function, then the solution consist of theese steps:
1. equation of line y=kx+b, where k and b - numbers, x and y coordinates of points.
2. using the equation of the line it is possible to substitute coordinates of points into equation:
$\left \{ {{-7=-8*k+b} \atop {-9=0*k+b}} \right. \ =\ \textgreater \ \ \left \{ {{-8k+b=-7} \atop {b=-9}} \right. \ =\ \textgreater \ \ \left \{ {{k=- \frac{1}{4}} \atop {b=-9}} \right.$
3. the equation is:
$y=- \frac{1}{4}x-9$