Question

abcd + 4707 = bcda 

 ai nhanh mik tick đúng cho

 

Answer 1

\(\overline{abcd}+4707=\overline{bcda}\)

\(\Rightarrow1000xa+\overline{bcd}+4707=10x\overline{bcd}+a\)

\(\Rightarrow999xa+4707=9x\overline{bcd}\)

\(\Rightarrow111xa+523=\overline{bcd}\)

Ta có \(\overline{bcd}\le999\Rightarrow111xa+523\le999\Rightarrow111xa\le999-523=476\)

\(\Rightarrow a\le4\)

+ Với \(a=0\Rightarrow\overline{bcd}=523\)

+ Với \(a=1\Rightarrow\overline{bcd}=111+523=634\)

+ Với \(a=2\Rightarrow\overline{bcd}=222+523=745\)

+ Với \(a=3\Rightarrow\overline{bcd}=333+523=856\)

+ Với \(a=4\Rightarrow\overline{bcd}=444+523=967\)

 

Answer 2

$\overline{abcd}+4707=\overline{bcda}$

$\Rightarrow 1000xa+\overline{bcd}+4707=10x\overline{bcd}+a$

$\Rightarrow 999xa+4707=9x\overline{bcd}$

$\Rightarrow 111xa+523=\overline{bcd}$

Ta có $\overline{bcd}\le 999\Rightarrow 111xa+523\le 999\Rightarrow 111xa\le 999-523=476$

$\Rightarrow a\le 4$

+ Với $a=0\Rightarrow \overline{bcd}=523$

+ Với $a=1\Rightarrow \overline{bcd}=111+523=634$

+ Với $a=2\Rightarrow \overline{bcd}=222+523=745$

+ Với $a=3\Rightarrow \overline{bcd}=333+523=856$

+ Với $a=4\Rightarrow \overline{bcd}=444+523=967$