2x cộng 8 chia hết cho2x công 1

Đáp án:

$x = 0\,\,hoac\,\,\,x = 3.$

Giải thích các bước giải: $\begin{array}{l} A = \frac{{2x + 8}}{{2x + 1}} = \frac{{2x + 1 + 7}}{{2x + 1}} = 1 + \frac{7}{{2x + 1}}\\ \Rightarrow \left( {2x + 8} \right)\,\, \vdots \,\,\left( {2x + 1} \right)\\ \Rightarrow 7\,\, \vdots \,\,\left( {2x + 1} \right)\\ Ma\,\,\,7\,\,chia\,\,het\,\,cho\,\,\,1\,\,va\,\,\,7\\ \Rightarrow \left[ \begin{array}{l} 2x + 1 = 1\\ 2x + 1 = 7 \end{array} \right. \Leftrightarrow \left[ \begin{array}{l} 2x = 0\\ 2x = 6 \end{array} \right. \Leftrightarrow \left[ \begin{array}{l} x = 0\\ x = 3 \end{array} \right..\\ Vay\,\,\,x = 0\,\,hoac\,\,\,x = 3. \end{array}$