\(\frac{x-1}{27}=\frac{-3}{1-x}\left(đkxđ:x\ne1\right)\\ \Leftrightarrow\frac{x-1}{27}=\frac{3}{x-1}\\ \Leftrightarrow\left(x-1\right)^2=27\cdot3\\ \Leftrightarrow\left(x-1\right)^2=81\\ \Rightarrow\left[{}\begin{matrix}x-1=9\\x-1=-9\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}x=10\\x=-8\end{matrix}\right.\\ Vậy...\)
\(\frac{x-1}{27}=\frac{-3}{1-x}\)
\(\Leftrightarrow x-1.1-x=27.\left(-3\right)\)
\(\left(x+x\right).\left(-1-1\right)=-81\)
\(2x.\left(-2\right)=-81\)
\(2x=-81\div(-2)\)
\(2x=40,5\)
\(x=20,25\)
