Giải thích các bước giải:
\[\begin{array}{l}
1,\\
{2.3^x} = {19.3^8} - {81^2}\\
\Leftrightarrow {2.3^x} = {19.3^8} - {\left( {{3^4}} \right)^2}\\
\Leftrightarrow {2.3^x} = {19.3^8} - {3^8}\\
\Leftrightarrow {2.3^x} = {18.3^8}\\
\Leftrightarrow {3^x} = {9.3^8}\\
\Leftrightarrow {3^x} = {3^{10}}\\
\Leftrightarrow x = 10\\
2,\\
{2^{x + 2}} - {2^x} = 48\\
\Leftrightarrow {2^x}{.2^2} - {2^x} = {3.2^4}\\
\Leftrightarrow {3.2^x} = {3.2^4}\\
\Leftrightarrow x = 4\\
3,\\
{5^x} = {5^{2019}}:\left( {{5^{2013}} - {{100.5}^{2010}}} \right)\\
\Leftrightarrow {5^x} = {5^{2019}}:\left( {{5^{2013}} - {{4.5}^2}{{.5}^{2010}}} \right)\\
\Leftrightarrow {5^x} = {5^{2019}}:\left( {{{5.5}^{2012}} - {{4.5}^{2012}}} \right)\\
\Leftrightarrow {5^x} = {5^{2019}}:{5^{2012}}\\
\Leftrightarrow {5^x} = {5^7}\\
\Leftrightarrow x = 7\\
4,\\
\left( {{5^2} + {3^2}} \right)x + \left( {{5^2} - {3^2}} \right)x - 40x = {10^2}\\
\Leftrightarrow x\left( {{5^2} + {3^2} + {5^2} - {3^2} - 40} \right) = 100\\
\Leftrightarrow x.\left( {{{2.5}^2} - 40} \right) = 100\\
\Leftrightarrow x.10 = 100\\
\Leftrightarrow x = 10
\end{array}\]
