You have to simplify each equation. You can do that by adding similar values to each other:
(the first equation)
8x²y + 7x² - 5y² + 3x - 2 + 2x²y - x² -  2y² + 3x - 4
To make it easier, arrange the values around so that similar ones are beside each other:
8x²y + 2x²y + 7x² - x² - 5y² - 2y² + 3x + 3x - 2 - 4
then add the similar values together:
8x²y + 2x²y = 10x²y
7x² - x² = 6x²
 - 5y² - 2y² = -7y²
 3x + 3x = 6x
(- 2)+ (- 4) = -6
and if you put them together: 
10x²y + 6x² - 7y² + 6x - 6
This isn't the answer to the equation, because it's different. So repeat the process with all the other equations until you find one that is identical to the simplified version.
The answer is the second one: 8x²y + 7x² - 5y² + 3x - 2 + 2x²y - x² -  2y² - 3x - 4
 
        
                    
             
        
        
        
The answer might be 4 meters.
Hope this helps !
Photon
        
                    
             
        
        
        
In order to find the answer to this question, you would need to find the Greatest Common Factor of 16 and 12 which would be 4 because 4 is the greatest amount that you can divide both 12 and 16 by. So the soonest both ships will leave together again will be in 4 days.
        
                    
             
        
        
        
Answer:
$236.40
Step-by-step explanation:
Mrs. Blanda's truck holds 19.7 gallons of gas. She used 4 full tanks of gas last month.
1 full tank  holds 19.7 gallons of gas
4 full tank hold 4*19.7 gallons of gas
4 full tank = 78.8 gallons of gas used last month
She paid $3 for each gallon
We need to find the amount she paid for 78.8 gallons
78.8 * 3= 236.4
Mrs. Blanda spend on gas last month = $236.40
 
        
             
        
        
        
Answer:
400 seconds
Step-by-step explanation:
150/20=7.5 meters per second
3000/7.5=400 seconds