The slope-intercept equation is y=mx+b.
The slope formula is ![\frac{y_{2}-y_{1} }{x_{2}-x_{1} }](https://tex.z-dn.net/?f=%5Cfrac%7By_%7B2%7D-y_%7B1%7D%20%20%7D%7Bx_%7B2%7D-x_%7B1%7D%20%20%7D)
Our three points are (5,5), (-5,-7) and (0,-1)
Using our slope formula our slope becomes ![\frac{-7-5}{-5-5} =\frac{12}{10} =\frac{6}{5}](https://tex.z-dn.net/?f=%5Cfrac%7B-7-5%7D%7B-5-5%7D%20%3D%5Cfrac%7B12%7D%7B10%7D%20%3D%5Cfrac%7B6%7D%7B5%7D)
Then, if we use one of our points (pick whichever you want, although (0,1) is the easiest) to solve the equation. So,
. When we solve for x and y, we get -1=0+b, or b=-1.
When we plug that back into the equation, we get
.