Thank you for the opportunity to help you with your question!
I am giving you the coordinates to use in each line because I can not draw it online.
17. (0, -3) (4,-2), (8,-1)
18. (-1,6), (0,5), (1,4)
19. (0, -6),(1, -3),((2,0)
You only have to look for a number you can multiply with x to get a y as a whole number.if you can look at all the coordinates I have given, you can see that I just though of the value of x which i can insert/substitute with x in each of the equation to get y
Please let me know if you need any clarification. I'm always happy to answer your questions.