Question

\(\dfrac{x-1}{2}=\dfrac{8}{x-1}\)

Answer 1

`(x-1)/2=8/(x-1)`

`=>(x-1)(x-1)=2.8`

`=>(x-1)^2=16`

`=>(x-1)^2=4^2` hoặc `(x-1)^2=(-4)^2` 

`=>x-1=4` hoặc `x-1=-4`

`=>x=5` hoặc `x=-3`

Vậy `x in{5;-3}`

Answer 2

\(\dfrac{x-1}{2}=\dfrac{8}{x-1}\)

\(\Rightarrow\left(x-1\right)^2=2\cdot8\)

\(\Rightarrow\left(x-1\right)^2=16\)

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

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

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

Vậy \(x\in\left\{-3;5\right\}\).

\(Toru\)

Answer 3

x-1/2 = 8/x-1

=>(x-1).(x-1) = 8.2

=>(x-1)^2 = 16

=> ( x-1)^2 = 4^2

-Trường hợp1:   x-1=4

                             x= 5

-Trường hợp 2:   x-1=-4

                            x=-3

--thodagbun--