Tìm số nguyên x, biết: x - 12 = 4

1) \(x - 12 = 4\)

\(\begin{array}{l}x = 4 + 12\\x = 16\end{array}\)

2) \(27 - \left( {12 + x} \right) = 23\)

\(\begin{array}{l}12 + x = 27 - 23\\12 + x = 4\\x = 4 - 12\\x = - 8\end{array}\)

3) \({\left( {2 + x} \right)^3}\; - 23 = {\rm{4}}\)

\(\begin{array}{l}{\left( {2 + x} \right)^3} = 4 + 23\\{\left( {2 + x} \right)^3} = {\rm{27}}\\{\left( {2 + x} \right)^3} = {3^3}\\2 + x = 3\\x = 3 - 2\\x = 1\end{array}\)

4) Vì 11 chia hết cho \(x\) nên \(x \in \) Ư(11).

Vậy \[x \in \left\{ { - 1;1; - 11;11} \right\}\].