Answer:
16. Parallelogram
17. x=3, y=9
Explanation:
16. You should graph it to get a visual. But using the given points, you can tell that the slopes for the lines AC and BD are the same, thus meaning those lines are parallel. The same for lines AD and BC.
17. 5x+2=17, so x= 3
3y-6=21, so y=9