a. \(x:\left(\dfrac{2}{3}\right)^4=\dfrac{2}{3}\)
\(\Rightarrow x:\dfrac{16}{81}=\dfrac{2}{3}\)
\(\Rightarrow x=\dfrac{2}{3}.\dfrac{16}{81}\)
\(\Rightarrow x=\dfrac{32}{243}\)
Vậy....
b. \(\left(\dfrac{-5}{3}\right)^2.x=\left(\dfrac{-5}{3}\right)^3\)
\(\Rightarrow x=\left(\dfrac{-5}{3}\right)^3:\left(\dfrac{-5}{3}\right)^2\)
\(\Rightarrow x=\dfrac{-5}{3}\)
Vậy....
c. \(x^2-0,25=0\)
\(\Rightarrow x^2=0+0,25\)
\(\Rightarrow x^2=0,25=\left(\pm0,5\right)^2\)
\(\Rightarrow\left[{}\begin{matrix}x=0,5\\x=-0,5\end{matrix}\right.\)
Vậy.........
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