Here, I'll do the first one for you.
When they are talking about a number, use "x".
Since it says twice a number, you say 2x. Or 3x for three times the number
2x+12=3x-31
Then use algebra to find x. Get the numbers on one side and all the x's on the other.
2x+12+31=3x-31+31
2x+43-2x=3x-2x
x=43
Now do the rest on your own!
        
             
        
        
        
Answer:
37.5
Step-by-step explanation:
the triangle is enlarged by a factor of 2.5 so you multiply all of the numbers in XYZ by 2.5 then add them 
15+10+12.5=37.5 units
 
        
                    
             
        
        
        
For x, the answer is x >= -(3 - y)/2, for y it's y <= 2x -3.
        
             
        
        
        
Your answer is 
B) 1/2
because there are 5 odd and 5 even numbers from 5 through 10, so it would be 1/2.
Glad I could help, and good luck!
        
                    
             
        
        
        
Answer:
$11/ day
Step-by-step explanation:
$44 /4 days
Divide the top and bottom by 4
44/4 = 11
$11/ day