Đáp án:
$\begin{array}{l}
\left( {{{10}^2} + {6^2}.2} \right):\left( {43:x} \right) = {20^0}\\
\Rightarrow \left( {100 + 36.2} \right):\left( {43:x} \right) = 1\\
\Rightarrow 172:\left( {43:x} \right) = 1\\
\Rightarrow 43:x = 172\\
\Rightarrow x = \dfrac{{43}}{{172}} = \dfrac{1}{4}\\
Vay\,x = \dfrac{1}{4}\\
4x - 20 = {2^5}:{2^3}\\
\Rightarrow 4x - 20 = {2^2}\\
\Rightarrow 4x = 20 + 4 = 24\\
\Rightarrow x = 6\\
Vay\,x = 6
\end{array}$
