Answer:
letter a
Step-by-step explanation:
a plus b equal to a
 
        
                    
             
        
        
        
Answer:
12, 25, 26, 26, 26, 34, 35, 39, 42, 42, 50, 72.
Step-by-step explanation:
A stem and leaf plot works like a digit separator. The left is the first number, which is usually repeated, and the right is the number you add to it.
In this example, 3 is used three times for the numbers 34, 35, and 39.
 
        
             
        
        
        
Answer:
-6
Step-by-step explanation:
 
        
                    
             
        
        
        
 Answer:
8x+24
dimensions of the photograph  
length - 7 inch  
width - 5 inch
dimensions of the photo frame is 2x larger than both width and length  
length - 7 + 2x
width - 5 + 2x
the perimeter is sum of all 4 sides  
Perimeter = 2(7 + 2x) + 2(5 + 2x)
                 = 14 + 4x + 10 +4x
                 = 24 + 8x
correct answer is 8x+24
 
        
             
        
        
        
Team A) 45 people
Team B) 55 people
A)There are two ways to solve this problem, finding the number of combinations possible for Team B, or the number of combinations possible for Team A. 
Team A
It's a given that 20 mathematicians are on team A, which leavs the other 25 people for team A to be chosen from a pool of 80 (100- 20 mathletes)
80-C-25 = 80! / (25!/(80-25)!) =<span>363,413,731,121,503,794,368
</span>or 3.63 x 10^20
Solving using Team B
Same concept, but choosing 55 from a pool of 80 (mathletes excluded)
80-C-25 = 80! / (55!(80-55!) = 363,413,731,121,503,794,368
or 3.63 x 10^20
As you can, we get the same answer for both. 
B)
If none of the mathematicians are on team A, then we exclude the 20 and choose 45:
80-C-45 = 80! / (45!(80-45)!) = <span>5,790,061,984,745,3606,481,440
or 5.79 x 10^22
Note that, if you solve from the perspective of Team B (80-C-35), you get the same answer</span>