I noticed there isn't a practice activity for Lesson 11. However, the attached lesson could be modified to meet the objective of the lesson and the prior knowledge obtained in IM 8. If the problems related to the slope of a vertical line (15-18 and 21-23 or rows 5 and 7) are deleted, then the lesson would be a great practice lesson for Unit 3 Lesson 11. 

https://www.khanacademy.org/math/algebra/x2f8bb11595b61c86:linear-equations-graphs/x2f8bb11595b61c86:horizontal-vertical-lines/e/horizontal-and-vertical-lines