40 boys and 68 girls
let's start with variables and an equation. 
boys: x
girls: 2x - 12
and we know that boys and girls make up the class. so let's add the two expressions.
x + 2x - 12 = 108
3x - 12 = 108
     + 12     + 12
3x = 120
x = 40 boys
BUT x is only the number of BOYS in the class. so we have to find girls now. let's plug in our value of x into the girls' equation.
2x - 12 = # of girls
2(40) -12 = # of girls
80 - 12 = # of girls
68 girls
let's check our answer!
68 + 40 does in fact add to 108, therefore our answer is correct. 
 
        
             
        
        
        
Hey there! 
1. The graph was flipped vertically and now opens downward. 
We know this because there is a negative sign in front of the equation: 
 
  
  
 
2. The graph was moved 3 units to the left. 
We know this because there is 3 added to x inside of the parenthesis. Remember, inside (parenthesis) is opposite and acts on x, outside (parenthesis) is same and acts on y. 
 
 
3. The graph was moved 5 units up. 
We know this because there is 5 added at the end of the equation. It acts on y because it is outside of the parenthesis. 

Hope this helps! 
 
        
             
        
        
        
Assuming you mean 2x-8y=7, we can start by multiplying the first equation by -2 and adding it to the second (to cross out the x), resulting in -18y=-5. After that, we can divide both sides by -18, resulting in y=5/18. Next, plugging that into 4x-2y=9, we have 4x-10/18=9. Adding 10/18 to both sides, we get 4x=9+10/18. After that, we can divide both sides by 4, resulting in x=(9+10/18)/4=
        
             
        
        
        
Answer: x=22
Step-by-step explanation:
Since the angles are corresponding angles, use x+14=5x-74. You get 36=36 meaning it is right when you substitute the value for x.
x+14=5x-74
-x on both sides
14=4x-74
+74 on both sides
88=4x
Divide both sides by 4
x=22