Answer:
here (edit I made a mistake)
Step-by-step explanation:
9) 
10) y = x - 3
11) 
12) 
these are the slop int forms, my bad...
sorry
Answer:
0 Siblings: 4 Students
3 or more siblings: 5 students
Step-by-step explanation:
The numbers at the bottom represents how many siblings they have and the dots represent the number of studens so using this we know:
0 Siblings: 4 Students
1 Sibling: 3 Students
2 Siblings: 3 Students
3 Siblings: 1 Student
4 Siblings: 0 Students
5 Siblings: 2 Students
6 Siblings: 1 Student
7 Siblings: 1 Student
3 or more: 1 + 0 + 2 + 1 + 1 = 5
3 or more siblings: 5 students
The answer is (-1,0) or x=-1 and y=0 :)