Answer:
The answer is  .
.
Step-by-step explanation:
First, it is important to recall that the group law is not commutative in general, so we cannot assume it here. In order to solve the exercise we need to remember the axioms of group, specially the existence of the inverse element, i.e., for each element  there exist another element, denoted by
 there exist another element, denoted by  such that
 such that  , where
, where  stands for the identity element of G.
 stands for the identity element of G.
So, given the equality  we make a left multiplication by
 we make a left multiplication by  and we obtain:
 and we obtain:

But,  . Hence,
. Hence,  .
.
Now, in the equality  we make a right multiplication by
 we make a right multiplication by  , and we obtain
, and we obtain
 .
. 
Recall that  and
 and  . Therefore,
. Therefore,
  .
.
 
        
             
        
        
        
Answer:
$72 
Step-by-step explanation:
I did 36 x 2. I did not subtract the -6 for the prize money because it says not to.
 
        
                    
             
        
        
        
Answer:
875
Step-by-step explanation:
30*15=450
30*10=300
20*5=100
12.5+12.5=25
450+300+100+25=875 
I worked from bottom to top 
 
        
                    
             
        
        
        
Answer:
36
Step-by-step explanation:
 
        
                    
             
        
        
        
Answer:
470 cm³
Step-by-step explanation:
Volume of rectangular prism = width × length × height
⇒ Volume of whole rectangular prism = 9 cm × 10 cm × 8 cm
                                                                 = 720 cm³
Side lengths of the missing piece:
- width  = 5 cm
- length = 10 cm
- height = 8 cm - 3 cm = 5 cm
⇒ Volume of the missing piece = 5 cm × 10 cm × 5 cm
                                                     = 250 cm³
⇒ Volume of irregular figure = 720 cm³ - 250 cm³
                                                 = 470 cm³