I believe that y=-1.5x-6 is the answer.
Answer: y=x+5/2
Step-by-step explanation:
using the slope intercept formula, y=mx+b where m is the slope and b is the y-intercept, you can substitute the two values to get y=x+5/2. Please note that the slope, m, is one so it's not shown.
It depends on how good the service was. it the service was really bad or just bad than maybe 2$, if the service was ok 5$ and finally if the service was extremely good and everything was just the way you like it then I would say tip 10$-20$