Đáp án:
b) x=-8
Giải thích các bước giải:
\(\begin{array}{l}
a)DK:x \ne \pm 4\\
M = \left( {\dfrac{{4x + 16 - 4x + 16}}{{\left( {x - 4} \right)\left( {x + 4} \right)}}} \right).\dfrac{{{{\left( {x + 4} \right)}^2}}}{{32}}\\
= \dfrac{{32}}{{\left( {x - 4} \right)\left( {x + 4} \right)}}.\dfrac{{{{\left( {x + 4} \right)}^2}}}{{32}}\\
= \dfrac{{x + 4}}{{x - 4}}\\
b)M = \dfrac{1}{3}\\
\to \dfrac{{x + 4}}{{x - 4}} = \dfrac{1}{3}\\
\to 3x + 12 = x - 4\\
\to 2x = - 16\\
\to x = - 8\\
c)M = 1\\
\to \dfrac{{x + 4}}{{x - 4}} = 1\\
\to x + 4 = x - 4\\
\to 4 = - 4\left( l \right)\\
\to x \in \emptyset
\end{array}\)
