Đáp án:
$\begin{array}{l}
a)x + 9 = 2 - 17\\
\Rightarrow x + 9 = - 15\\
\Rightarrow x = - 15 - 9\\
\Rightarrow x = - 24\\
b)15 - 4.x = 47\\
\Rightarrow 4.x = 15 - 47\\
\Rightarrow 4.x = - 32\\
\Rightarrow x = \frac{{ - 32}}{4}\\
\Rightarrow x = - 8\\
c)\left| {x - 5} \right| = {\left( { - 4} \right)^2}\\
\Rightarrow \left| {x - 5} \right| = 16\\
\Rightarrow \left[ \begin{array}{l}
x - 5 = 16\\
x - 5 = - 16
\end{array} \right.\\
\Rightarrow \left[ \begin{array}{l}
x = 16 + 5\\
x = - 16 + 5
\end{array} \right.\\
\Rightarrow \left[ \begin{array}{l}
x = 21\\
x = - 11
\end{array} \right.\\
d) - 2.\left| {x - 4} \right| + 17 = - 9\\
\Rightarrow 2\left| {x - 4} \right| = 17 + 9\\
\Rightarrow 2.\left| {x - 4} \right| = 26\\
\Rightarrow \left| {x - 4} \right| = \frac{{26}}{2} = 13\\
\Rightarrow \left[ \begin{array}{l}
x - 4 = 13\\
x - 4 = - 13
\end{array} \right.\\
\Rightarrow \left[ \begin{array}{l}
x = 13 + 4 = 17\\
x = - 13 + 4 = - 9
\end{array} \right.
\end{array}$
Vậy x=17 hoặc x=-9
