Answer:
The third option.
Step-by-step explanation:

Hence the 3rd option.
 
        
             
        
        
        
You just need to plug those expressions inside the formula: it doesn't matter if they're expressions involving a variable instead of plain numbers: the formula becomes

If you want, you can simplify it by expanding the square and then multiply the two parenthesis:

 
        
             
        
        
        
Answer: False
Step-by-step explanation:
For this to be true; x must be squared.
 
        
             
        
        
        
In order to determine the number of boys in the class, first, we set-up an algebraic equation. Let x = number of boys in the class. The equation is then: x + 4x = 45. This is because the number of girls is 4 times greater than the number of boys. After solving the algebraic equation, it is then determined that there are 9 boys in the Chemistry class.   
        
             
        
        
        
Answer:
Step-by-step explanation:
according to the question ur equation is
9y-8(a+b)
9y-8a-8b