Giải thích các bước giải:
Ta có:
\(\begin{array}{l}
b,\\
{4^{2x - 1}}:4 = 16\\
\Leftrightarrow {4^{2x - 1}} = 4.16\\
\Leftrightarrow {4^{2x - 1}} = {4.4^2}\\
\Leftrightarrow {4^{2x - 1}} = {4^3}\\
\Leftrightarrow 2x - 1 = 3\\
\Leftrightarrow 2x = 4\\
\Leftrightarrow x = 2\\
d,\\
36:\left( {x - 5} \right) = {2^2}\\
\Leftrightarrow x - 5 = 36:{2^2}\\
\Leftrightarrow x - 5 = 36:4\\
\Leftrightarrow x - 5 = 9\\
\Leftrightarrow x = 9 + 5\\
\Leftrightarrow x = 14\\
f,\\
\left[ {3.\left( {70 - x} \right) + 5} \right]:2 = 46\\
\Leftrightarrow 3.\left( {70 - x} \right) + 5 = 46.2\\
\Leftrightarrow 3.\left( {70 - x} \right) + 5 = 92\\
\Leftrightarrow 3.\left( {70 - x} \right) = 92 - 5\\
\Leftrightarrow 3.\left( {70 - x} \right) = 87\\
\Leftrightarrow 70 - x = 87:3\\
\Leftrightarrow 70 - x = 29\\
\Leftrightarrow x = 70 - 29\\
\Leftrightarrow x = 41
\end{array}\)
