2 câu trả lời
$\begin{array}{l} 3x - 2\left( {x + 5} \right) = 71\\ 3x - 2x - 10 = 71\\ x - 10 = 71\\ x = 71 + 10\\ x = 81. \end{array}$
$\begin{array}{l} 3x - 2\left( {x + 5} \right) = 71\\ 3x - 2x - 10 = 71\\ x - 10 = 71\\ x = 71 + 10\\ x = 81. \end{array}$