Giải thích các bước giải:
a) $3^{x+1}= 9\Leftrightarrow 3^{x+1}= 3^{2}\Leftrightarrow x+1= 2\Leftrightarrow x= 1$
b) $5^{2x-4}-1= 0\Leftrightarrow 5^{2x-4}= 1\Leftrightarrow 5^{2x-4}= 5^{0}\Leftrightarrow 2x-4=0\Leftrightarrow x= 2$
c) $\left ( -5 \right )^{x+3}= -\frac{1}{125}\Leftrightarrow \left ( -5 \right )^{x+3}. \left ( -125 \right )=1$
$\Leftrightarrow \left ( -5 \right )^{x+3}.\left ( -5 \right )^{3}= \left ( -5 \right )^{0}$
$\Leftrightarrow \left ( -5 \right )^{x+6}= \left ( -5 \right )^{0}\Leftrightarrow x+6= 0\Leftrightarrow x=-6$
d) $2^{6+5x}= 16^{9}\Leftrightarrow 2^{6+5x}= 2^{36}\Leftrightarrow 6+5x= 36\Leftrightarrow x= 6$
