Giải thích các bước giải:
\(\begin{array}{l}
1.\left[ \begin{array}{l}
x = 0\\
x + 7 = 0
\end{array} \right. \to \left[ \begin{array}{l}
x = 0\\
x = - 7
\end{array} \right.\\
2.\left[ \begin{array}{l}
x + 12 = 0\\
x - 3 = 0
\end{array} \right. \to \left[ \begin{array}{l}
x = - 12\\
x = 3
\end{array} \right.\\
3.\left[ \begin{array}{l}
- x + 5 = 0\\
3 - x = 0
\end{array} \right. \to \left[ \begin{array}{l}
x = 5\\
x = 3
\end{array} \right.\\
4.\left[ \begin{array}{l}
x = 0\\
2 + x = 0\\
7 - x = 0
\end{array} \right. \to \left[ \begin{array}{l}
x = 0\\
x = - 2\\
x = 7
\end{array} \right.
\end{array}\)
\(5.\left[ \begin{array}{l}
x - 1 = 0\\
x + 2 = 0\\
- x - 3 = 0
\end{array} \right. \to \left[ \begin{array}{l}
x = 1\\
x = - 2\\
x = - 3
\end{array} \right.\)
