Đáp án:x= 1/100
Giải thích các bước giải:
$\begin{array}{l}
{4^{\lg x + 1}} - {6^{\lg x}} - {2.3^{\lg {x^2} + 2}} = 0\\
\Rightarrow {4.2^{2\left( {\lg x} \right)}} - {2^{\lg x}}{.3^{\lg x}} - {2.9.3^{2\lg x}} = 0\\
\Rightarrow 4.\frac{{{2^{2\lg x}}}}{{{3^{2\lg x}}}} - \frac{{{2^{\lg x}}}}{{{3^{\lg x}}}} - 18 = 0\,\left( {vi\,{3^{\lg x}} > 0\,nen\,chia\,2\,ve\,cho\,{3^{\lg x}}} \right)\\
\Rightarrow \left[ \begin{array}{l}
\frac{{{2^{\lg x}}}}{{{3^{\lg x}}}} = \frac{9}{4}\\
\frac{{{2^{\lg x}}}}{{{3^{\lg x}}}} = - 2\left( {loai} \right)
\end{array} \right. \Rightarrow {\left( {\frac{2}{3}} \right)^{\lg x}} = {\left( {\frac{2}{3}} \right)^{ - 2}}\\
\Rightarrow \lg x = - 2\\
\Rightarrow x = {10^{ - 2}} = \frac{1}{{100}}
\end{array}$
