Answer:
He started with 180.
Step-by-step explanation:
If 90 is 50% of what he started with, then the other 50% is 90
 
        
             
        
        
        
Answer:
there are two solutions:
a)  , and
, and
b) 
Step-by-step explanation:
In the equation:  , since a perfect square with the unknown "y" is isolated on the left of the equal sign, we start by applying the square root on both sides of the equality, and then on isolating the unknown:
, since a perfect square with the unknown "y" is isolated on the left of the equal sign, we start by applying the square root on both sides of the equality, and then on isolating the unknown:

Therefore there are two solutions:
a)  , and
, and
b) 
 
        
                    
             
        
        
        
Both of the problems equal 600
        
             
        
        
        
Answer:

Step-by-step explanation:
Either you wanted me to simplify all those variables or you just had a seizure on your keyboard.
 
        
             
        
        
        
Answer:
6/3
Step-by-step explanation: