\(\begin{array}{l}18 - x + \left[ {8 - 13{\rm{ }}} \right] = 15 - \left[ { - 2} \right]\\ \Leftrightarrow 18 - x + \,\,\left( { - 5} \right) = 15 + 2\\ \Leftrightarrow 18 - x = 17 + 5\\ \Leftrightarrow 18 - x = 22\\ \Leftrightarrow x = 18 - 22\\ \Leftrightarrow x = - 4\end{array}\)
