1. 8 
2. 15
3. 2
4. 1/2 
5. 3 
those are the answers in order, hope this helps!
        
             
        
        
        
Using a system of equations, it is found that the correct option is:
A) 1389x+1660y=787x+1121y.
<h3>What is a system of equations?</h3>
A system of equations is when two or more variables are related, and equations are built to find the values of each variable.
In this problem, considering the amounts in each olympics(1389 men and 787 women participated on the 19th, 1660 men and 1121 women in the 22th), the system is:
A) 1389x+1660y=787x+1121y.
More can be learned about a system of equations at brainly.com/question/24342899
 
        
             
        
        
        
Answer:
8
Step-by-step explanation:
Use the Pythagorean theorem.
a^2 + 6^2 = 10^2
a^2 + 36 = 100
a^2 = 64
a = 8
 
        
             
        
        
        
You are given that all three sides are equal. You also know that all three angles are also equal. Therefore since all three angles are equal and every triangle has 180 degrees, each angle is 180/3 = 60
So 
7x - 3 = 60                     Add three to both sides
7x - 3 + 3 = 60 + 3        Combine
7x = 63                          Divide by 7
7x/7 = 63/7
x = 9                              And that's your answer.
 
        
             
        
        
        
Factor the following:
12 x^2 y - 32 x y + 8 y
Hint: | Factor common terms out of 12 x^2 y - 32 x y + 8 y.
Factor 4 y out of 12 x^2 y - 32 x y + 8 y:
Answer:  4 y (3 x^2 - 8 x + 2)