Answer: A: -25/2
Step-by-step explanation:
 
        
             
        
        
        
tenths because 42.02 it would be tenths the first decimal is tenths and second is hundreths
 
        
             
        
        
        
Answer:
-256
Step-by-step explanation:
 
        
                    
             
        
        
        
Answer:
The augmented matrix of the system is ![\left[\begin{array}{cccc}2&3&-1&14\\1&2&1&4\\5&9&2&7\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bcccc%7D2%263%26-1%2614%5C%5C1%262%261%264%5C%5C5%269%262%267%5Cend%7Barray%7D%5Cright%5D) .
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We apply operations rows:
1. We swap row 1 and 2 and obtain the matrix ![\left[\begin{array}{cccc}1&2&1&4\\2&3&-1&14\\5&9&2&7\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bcccc%7D1%262%261%264%5C%5C2%263%26-1%2614%5C%5C5%269%262%267%5Cend%7Barray%7D%5Cright%5D) .
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2. Of the above matrix we subtract row 1 from row 2 twice (R2 - 2R1) and we subtract row 1 from row 3, 5 times. (R3-5R1). We obtain the matrix ![\left[\begin{array}{cccc}1&2&1&4\\0&-1&-3&6\\0&-1&-3&-13\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bcccc%7D1%262%261%264%5C%5C0%26-1%26-3%266%5C%5C0%26-1%26-3%26-13%5Cend%7Barray%7D%5Cright%5D)
3. Of the above matrix we subtract row 2 from row1 twice (R3 - R2) and multiply the row 1 by -1 (-R2). Weobtain the matrix ![\left[\begin{array}{cccc}1&2&1&4\\0&1&3&-6\\0&0&0&-19\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bcccc%7D1%262%261%264%5C%5C0%261%263%26-6%5C%5C0%260%260%26-19%5Cend%7Barray%7D%5Cright%5D) .
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Since each pivote is an one then we conclude that the above matrix is the reduced row-echelon form of the matrix of the system.