The correct option would be C
        
             
        
        
        
Answer:
the answer is 30
Step-by-step explanation:
 
        
                    
             
        
        
        
Multiply the numerator by the numerator (top number). 
Multiply the denominator by the denominator (bottom number). 
So 3 x 6 = 18 
And 5 x 7 = 35 
= 18/35 
        
                    
             
        
        
        
The first is a. you can rewrite it

the second is d. the only common factor between 20 and 40 that can be taken out is the 4 which becomes a 2, but inside the square roots there is still a 5 and 10, which cannot be combined
the third is c.

the fourth is d.
add 3 to both sides 

then square both sides 

then divide both sides by 2, x=50