1. 

2. 

3. -7/30
4. i believe it is the communitive of multiplication , but not 100% sure
 
        
        
        
14.49. 
To get ST is the square root of the product of QT and RT, so the square root of 
30 x 7 == the square root of 210.
        
             
        
        
        
The answer is (4,8). I hope this helps.
        
                    
             
        
        
        

For m = 0.6213, 

For m = -3.6213, 

Therefore, the equation has no extraneous solution.