Use the following word problem for questions 7 and 8 below. A total of 564 tickets were sold for the school play. They were either adult tickets or student tickets. The number of student tickets sold was three times the number of adult tickets sold. How many adult tickets were sold? 7) Which equation below could be used to find the number of adult tickets that were sold. *

7 + 8x = 564
7x + 8x = 564
A + 3A = 564
A + 3 = 564
3A = 564