\(a,x=\dfrac{-10}{21}.\dfrac{-3}{5}\)
\(\Rightarrow x=\dfrac{2}{7}\)
\(b,\dfrac{-2}{3}x=\dfrac{1}{10}\)
\(\Rightarrow x=\dfrac{-3}{20}\)
\(c,\left(x^2+\dfrac{1}{25}\right)+\dfrac{17}{25}=\dfrac{26}{25}\)
\(\left(x^2+\dfrac{1}{25}\right)=\dfrac{9}{25}\)
\(x^2=\dfrac{8}{25}\)
\(\Rightarrow x=\dfrac{2\sqrt{2}}{5}\)
Giải:
a) \(x:-\dfrac{3}{5}=-\dfrac{10}{21}\)
\(x=-\dfrac{10}{21}.-\dfrac{3}{5}\)
\(x=\dfrac{2}{7}\)
b) \(-\dfrac{2}{3}x+\dfrac{1}{5}=\dfrac{3}{10}\)
\(-\dfrac{2}{3}x=\dfrac{3}{10}-\dfrac{1}{5}\)
\(-\dfrac{2}{3}x=\dfrac{1}{10}\)
\(x=\dfrac{1}{10}:-\dfrac{2}{3}\)
\(x=-\dfrac{3}{20}\)
c) \(\left(x+\dfrac{1}{5}\right)^2+\dfrac{17}{25}=\dfrac{26}{25}\)
\(\left(x+\dfrac{1}{5}\right)^2=\dfrac{26}{25}-\dfrac{17}{25}\)
\(\left(x+\dfrac{1}{5}\right)^2=\dfrac{9}{25}\)
\(\Rightarrow\left[{}\begin{matrix}\left(x+\dfrac{1}{5}\right)^2=\left(\dfrac{3}{5}\right)^2\\\left(x+\dfrac{1}{5}\right)^2=\left(-\dfrac{3}{5}\right)^2\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x+\dfrac{1}{5}=\dfrac{3}{5}\\x+\dfrac{1}{5}=-\dfrac{3}{5}\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x=\dfrac{2}{5}\\x=-\dfrac{4}{5}\end{matrix}\right.\)
d) \(\left(x+\dfrac{1}{2}\right).\left(\dfrac{2}{3}-2x\right)=0\)
\(\Rightarrow\left[{}\begin{matrix}x+\dfrac{1}{2}=0\\\dfrac{2}{3}-2x=0\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x=\dfrac{-1}{2}\\x=\dfrac{1}{3}\end{matrix}\right.\)
