Answer:
The slope is 9, so your friend saves $9 every week
Step-by-step explanation:
We are given the point (3,39) and below it on the line (2,30).
[tex]y1-x1/y2-x2[/tex] (Note its supposed to be y 'sub' 1 ect...)
Just plug the points in with the formula and you'll get the answer!
