Answer:
first one: <u>3</u>
second one: <u>b</u>
third one: <u>3.2</u>
Step-by-step explanation:
first one:
21 x ________ ÷ 3 = 21 
rewrite equation:
21 ÷ 3 x ___ = 21
7 x ___ = 21
(21 / 7 = 3)
7 x 3 = 21 
second one: 
b x h ÷ h = ___
B 
 third one:
876 x 3.2 ÷ ______ = 876
2803.2 ÷ ___ = 876
(2803.2 / 876 = 3.2)
2803.2 x 3.2 = 876 
 
        
             
        
        
        
This question wants you to divide 32 tables by 6 students which is 5.3333. Since 5 tables is not enough, 6 tables are needed.
        
             
        
        
        
8*a=32
32:8=a
4=a
4+26=b
30=b
        
             
        
        
        
Plog in to y=ax+b and u will find a b