The given is that A B C D <span>x 4 = D C B A
</span><span>
Possible values of A are 1 or 2. It can't be 1 since the </span><span> </span><span>final result A is in unit place and 1 is not possible when we multiply any number by 4
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2 B C D x </span><span>4 = </span><span>D C B 2</span>
It is clear above, that D = 8
2 B C 8 x <span>4 = </span><span>8 C B 2</span>
Possible values of B should be 1 or 2
We try B=1
2 1 C 8 x <span>4 = </span><span>8 C 1 2
</span>To find for C, you can use the equation:
(2000+100+10C+8) x 4 = 8000+100C+10+240C = 432-12 = 420
Therefore,
C = 7
So, the number is 2178.
        
                    
             
        
        
        
The answer is A.) 3x-7y and -7y+3x
This is due to "3x" implies the value is positive, or "+3x", and -7y remains -7y.
So, we have 3x-7y and -7y+3x.
I hope this helps!
        
                    
             
        
        
        
Answer: p(-3)=18
Step-by-step explanation:
To find p(-3), you plug -3 into p(x) and solve.
p(-3)=(-3)²-3(-3)               [exponent]
p(-3)=9-3(-3)                    [multiply]
p(-3)=9+9                         [add]
p(-3)=18
Now we found that p(-3)=18.
 
        
             
        
        
        
Answer:
Helena gave the answer as (7y²z + 6yz²- 5 - 3yz² + 2) which is equivalent to (7y²z + 3yz² - 3).
Step-by-step explanation:
Misha's group was asked to write an expression equivalent to  
7y²z + 3yz² - 3
When Mr. Chen checked their answers, he found only one to be correct.
And she was Helena.
Helena gave the answer as (7y²z + 6yz²- 5 - 3yz² + 2) which is equivalent to (7y²z + 3yz² - 3).  
Because, (7y²z + 6yz²- 5 - 3yz² + 2)
= 7y²z + (6yz² - 3yz²) - (5 - 2)  
= 7y²z + 3yz² - 3 (Answer)