Question

http://prntscr.com/d96rva

Answer 1

Know rise over run? \[\frac{ y_2-y_1 }{ x_2-x_1 } = \frac{ rise }{ run }\] or you can count from (0,-4) to (2,-3)

Answer 2

@alison_doge
Note: a linear function means a line.

First, you need to find two points that pass through the intersection of grid points (if possible). This will help you find the difference along the x- and y-axes accurately.

If it is not possible, you will need to arbitrarily find two points and estimate their coordinates. If there are more than two possible points, find the points furthest away from each other to increase the accuracy.

@Astrophysics has already done this first step for you. The points are
R(0,-4) and S(2,-3).
The slope, m, of the line joining two points R and S with coordinates \(R(x_1,y_1)\) and \(S(x_2,y_2)\) is given by the following formula:

\(\bbox [10pt, lightgrey, border:3pt solid green]{\large m=\frac{y_2-y_1}{x_2-x_1}}\)

It is a handy formula to keep in your math toolbox.