a: Ta có: \(\dfrac{1.8}{1.3}=\dfrac{-2.7}{5x}\)
\(\Leftrightarrow5x=-\dfrac{39}{20}\)
hay \(x=-\dfrac{39}{100}\)
b: ta có: \(\dfrac{-\dfrac{1}{2}}{2x-1}=\dfrac{0.2}{-\dfrac{3}{5}}\)
\(\Leftrightarrow2x-1=\dfrac{3}{2}\)
hay \(x=\dfrac{5}{4}\)
d: ta có: \(-\dfrac{9}{x}=\dfrac{-x}{\dfrac{4}{9}}\)
\(\Leftrightarrow x^2=4\)
hay \(x\in\left\{2;-2\right\}\)
\(a,1,8:1,3=\left(-2,7\right):\left(5x\right)\\ \Rightarrow\dfrac{18}{13}=\dfrac{-27}{50x}\\ \Rightarrow900x=-351\\ \Rightarrow x=-\dfrac{39}{100}\\ d,\dfrac{-9}{x}=\dfrac{-x}{\dfrac{4}{9}}\\ \Rightarrow x^2=-9\left(-\dfrac{4}{9}\right)=4\\ \Rightarrow x=\pm2\)
\(b,\dfrac{-\dfrac{1}{2}}{2x-1}=\dfrac{0,2}{\dfrac{-3}{5}}\\ \Rightarrow x-0,2=-\dfrac{1}{2}\left(-\dfrac{3}{5}\right)\\ \Rightarrow x-\dfrac{1}{5}=\dfrac{3}{10}\\ \Rightarrow x=\dfrac{3}{10}+\dfrac{1}{5}=\dfrac{1}{2}\\ e,\dfrac{3}{1-2x}=\dfrac{-5}{3x-2}\\ \Rightarrow10x-5=9x-6\\ \Rightarrow x=-1\)
e: Ta có: \(\dfrac{3}{1-2x}=\dfrac{-5}{3x-2}\)
\(\Leftrightarrow9x-6=-5+10x\)
\(\Leftrightarrow-x=1\)
hay x=-1
