a) \(\dfrac{x}{27}=-\dfrac{1}{9}\)
\(\Rightarrow x=\dfrac{27\cdot-1}{9}\)
\(\Rightarrow x=-3\)
b) \(\dfrac{-2}{x}=\dfrac{9}{-12}\)
\(\Rightarrow\dfrac{-2}{x}=\dfrac{3}{-4}\)
\(\Rightarrow x=\dfrac{-2\cdot-4}{3}\)
\(\Rightarrow x=\dfrac{8}{3}\)
c) \(\dfrac{x}{5}=\dfrac{20}{x}\)
\(\Rightarrow x\cdot x=20\cdot5\)
\(\Rightarrow x^2=100\)
\(\Rightarrow x^2=10^2\)
\(\Rightarrow x=\pm10\)
d) \(\dfrac{3}{8}=\dfrac{x}{32}\)
\(\Rightarrow x=\dfrac{3\cdot32}{8}\)
\(\Rightarrow x=12\)
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