20/2-10/5. You divide 20 by 2 and subtract that from 10 divided by 5
        
             
        
        
        
Answer:
48390,"37,520","65,810",2170 or 2180 (both will work)
 
        
                    
             
        
        
        
1. when you see 4(x² - 1), then you have to multiply 4 with everything in the bracket. keep in mind that you always have to be cautious of the sign whether it is a positive or a negative. 
positive ×/÷ positive = positive
negative ×/÷ negative = positive
positive ×/÷ negative = negative
negative ×/÷ positive = negative
^ you have to remember this. 
2. only like terms (same alphabet) can plus or minus each other. 
3. simplify by taking out the common factor and placing it outside the bracket.
 
        
        
        
Answer: -3x + 4, (2,-2)
Step-by-step explanation:
First, you want to get y alone on one side. 
3x + y = 4
      -4    -4        subtract 4 to get it on the left side.
      -y     -y       subtract y to get it alone on the right side.
Your'e left with 3x - 4 = -y      divide the whole equation by -1 do get a pos y
You then have y = -3x + 4. That's the first part of your answer.
To get the second part plug in (-3x + 4) into the y of the first equation, this is the substitution part.
-2x + 5(-3x+4) =-14        distribute the 5...     -2x - 15x +20 = -14
add your like terms ( x and x)                       -17x + 20 = -14
Isolate your x by subtracting the 20, both sides  -20   -20
-17x = -34    divide both side by 17 you get x = 2 (---- this is your first coordinate in the pair in your answer. To get the y do the same but solve for y instead of x. 
 
        
             
        
        
        
Answer:
I'm pretty sure your answer would be B
Step-by-step explanation:
The teacher wants answers from all the students but it would take to long to ask every single person so it would only make sense to ask every boy in each grade