\(3x\left( {x + 2} \right) - x\left( {3x + 5} \right) = 5\)
Giải chi tiết:
\(3x\left( {x + 2} \right) - x\left( {3x + 5} \right) = 5\)
\(\begin{array}{l}\,\,\,\,\,\,\,3x\left( {x + 2} \right) - x\left( {3x + 5} \right) = 5\\ \Leftrightarrow \left( {3{x^2} + 6x} \right) - \left( {3{x^2} + 5x} \right) = 5\\ \Leftrightarrow 3{x^2} + 6x - 3{x^2} - 5x = 5\\ \Leftrightarrow x = 5\end{array}\)
Vậy \(x = 5\).