Thay $x$ bằng chữ số thích hợp để số $\overline {x6257}$ chia cho $3$ dư $1$ .

$\left( {a + b} \right) \in \left\{ {9;18} \right\}$                                              

$\left( {a + b} \right)\in \left\{ {0;9;18} \right\}$

$\left( {a + b} \right) \in \left\{ {1;2;3} \right\}$                                                 

$\left( {a + b} \right)\in \left\{ {4;5;6} \right\}$

A. $b = 1\,;\,\,4\,;\,\,7$

B. $b = 2\,;\,\,5\,;\,\,8$

C. $b = 3\,;\,\,6\,;\,\,\,9$

D. $b = 0\,;\,\,3\,;\,\,6\,;\,\,9$

$3$

$4$      

$5$                                    

$6$

$x = 0;y = 6$  

$x = 6;y = 0$      

$x = 8;y = 0$         

$x = 0;y = 8$

$3$                                              

$4$

$2$    

$1$