Question

Answer 1

\(\dfrac{x-1}{3}=\dfrac{27}{x-1}\)

\(\Leftrightarrow\left(x-1\right)^2=81\)

\(\Leftrightarrow\left[{}\begin{matrix}x-1=9\\x-1=-9\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=10\\x=-8\end{matrix}\right.\)

Answer 2

\(\dfrac{x-1}{3}=\dfrac{27}{x-1}\left(đk:x\ne1\right)\)

\(\Leftrightarrow\left(x-1\right)^2=3.27\)

\(\Leftrightarrow\left(x-1\right)^2=81\)

\(\Leftrightarrow\left[{}\begin{matrix}x-1=9\\x-1=-9\end{matrix}\right.\)\(\Leftrightarrow\left[{}\begin{matrix}x=10\left(tm\right)\\x=-8\left(tm\right)\end{matrix}\right.\)