Step-by-step explanation:
Sorry to say, but there is no picture... 
 
        
             
        
        
        
Answer:
15
Step-by-step explanation:
75/5 = 15
This spilts the 75 students into 5 different groups and each one has 15 which is 1/5 of the students
 
        
             
        
        
        
Answer:
Yes
Step-by-step explanation:
For number 3 you answered them all correctly as well as number 4 and 5. Don't hesitate asking questions like these :D
 
        
             
        
        
        
Step-by-step explanation:
3x+9+4x-3+8x-6=180
15x=180
x=12
angle 1= 3x+9=36+9=45°
angle 2=4x-3=48-3=45°
angle 3=8x-6=96-6=90°
1) it's right triangle
2) it's isosceles triangle