Đáp án:
$\begin{array}{l}
d)\dfrac{{54}}{{{3^{x - 2}}}} = 2\\
\Leftrightarrow {3^{x - 2}} = 54:2\\
\Leftrightarrow {3^{x - 2}} = 27\\
\Leftrightarrow {3^{x - 2}} = {3^3}\\
\Leftrightarrow x - 2 = 3\\
\Leftrightarrow x = 5\\
Vậy\,x = 5\\
g)\dfrac{9}{{{{27}^x}}} = \dfrac{{{3^{x + 1}}}}{{81}}\\
\Leftrightarrow 9.81 = {27^x}{.3^{x + 1}}\\
\Leftrightarrow {3^2}{.3^4} = {3^{3x}}{.3^{x + 1}}\\
\Leftrightarrow 2 + 4 = 3x + x + 1\\
\Leftrightarrow 4x = 5\\
\Leftrightarrow x = \dfrac{5}{4}\\
Vậy\,x = \dfrac{5}{4}\\
n){\left( {3x + 4} \right)^2} = 16\\
\Leftrightarrow \left[ \begin{array}{l}
3x + 4 = 4\\
3x + 4 = - 4
\end{array} \right.\\
\Leftrightarrow \left[ \begin{array}{l}
3x = 0\\
3x = - 8
\end{array} \right.\\
\Leftrightarrow \left[ \begin{array}{l}
x = 0\\
x = - \dfrac{8}{3}
\end{array} \right.\\
Vậy\,x = 0;x = - \dfrac{8}{3}\\
j){\left( {x - 2} \right)^2} = 1\\
\Leftrightarrow \left[ \begin{array}{l}
x - 2 = 1\\
x - 2 = - 1
\end{array} \right.\\
\Leftrightarrow \left[ \begin{array}{l}
x = 3\\
x = 1
\end{array} \right.\\
Vậy\,x = 1;x = 3
\end{array}$
