Question

Tìm x biết :

\(\dfrac{x-1}{-4}=\dfrac{-4}{x-1}\)

Answer 1

\(\dfrac{x-1}{-4}=\dfrac{-4}{x-1}\left(x\ne1\right)\)

\(\Rightarrow\left(x-1\right)\cdot\left(x-1\right)=\left(-4\right)\cdot\left(-4\right)\)

\(\Rightarrow\left(x-1\right)^2=4^2\)

TH1: \(x-1=4\Rightarrow x=4+1=5\left(tm\right)\)

TH2: \(x-1=-4\Rightarrow x=-4+1=-3\left(tm\right)\) 

Answer 2

\(\dfrac{x-1}{-4}=\dfrac{-4}{x-1}\left(dk:x\ne1\right)\)

\(\Rightarrow\left(x-1\right)\cdot\left(x-1\right)=-4\cdot\left(-4\right)\)

\(\Rightarrow\left(x-1\right)^2=\left(\pm4\right)^2\)

\(\Rightarrow\left[{}\begin{matrix}x-1=4\\x-1=-4\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=5\\x=-3\end{matrix}\right.\left(tm\right)\)