Đáp án:
$a) x=\dfrac{7}{8}\\
b)x=80\\
c) x=\pm 12\\
d) x=\pm \dfrac{8}{5}$
Giải thích các bước giải:
$a) -0,375:x=-3,63:8,47\\
\Leftrightarrow -0,375:x=\dfrac{-3}{7}\\
\Leftrightarrow x=-0,375:\dfrac{-3}{7}=\dfrac{7}{8}\\
b) (0,25.x):3=\dfrac{5}{6}:0,125\\
\Leftrightarrow 0,25x=\dfrac{20}{3}.3\\
\Leftrightarrow x=20:0,25=80\\
c) \dfrac{x}{-16}=\dfrac{-9}{x}\\
\Leftrightarrow x^2=(-9).(-16)=144\\
\Leftrightarrow x=\pm 12\\
d) \dfrac{-16}{x}=\dfrac{-x}{\dfrac{4}{25}}\\
\Leftrightarrow x^2=16.\dfrac{4}{25}\\
\Leftrightarrow x^2=\dfrac{64}{25}\\
\Leftrightarrow x=\pm \dfrac{8}{5}$
