As we are given with 

we are supposed to simplify this expression. which can be done as below


 
        
             
        
        
        
How to solve:
Step 1 :  Note down the given ratio from the questions.
Step 2 :  <span>Find the greatest common factor, and divide the numerator and denominator by that value.
Answer: 3:7</span>
        
             
        
        
        
The dimensions are factors of the expression 
... you multiply them together to get the area 
the factors are ... (x - 7) & (x + 2)
        
             
        
        
        
Answer:
B
Step-by-step explanation:
did the math for it!!