Answer:
(12 + 3x)x
Step-by-step explanation:
(12 + 3)x = 12x + 3x = 15x
(12 + 3x)x = 12x + 3x²
15x
12x + 3x = 15x
They all equal 15x except for (12 + 3x)x
 
        
             
        
        
        
Answer:
16.2
Step-by-step explanation:
By geometric mean theorem:

 
        
             
        
        
        
Answer:
Step 2 has the error
1. The whole number (20) was left out
2. Adding different signs, we subtract and retain the sign from the larger number
Correction: 
Step 2: 20 - 17x = 34x + 60
Step 3: -17x -34x = 60 - 20
Step 4: -51x = 40
Step 5: x = 40/-51
 
        
                    
             
        
        
        
Answer:
27 and 40
Step-by-step explanation:
 
        
             
        
        
        
 A because 2x9 equals 18 and 9x2 equals 18