=>(x-2)^2=1

=>x-2=1 hoac x-2=-1

=>x=3 ; x=1

\(\frac{0.4}{x}=\frac{x}{0,9}\)

\(\Leftrightarrow0,4.0,9=x.x\)

\(\Leftrightarrow0,36=x^2\)

\(\Leftrightarrow\frac{9}{25}=x^2\)

\(\Leftrightarrow\hept{\begin{cases}\left(\frac{3}{5}\right)^2=x^2\\\left(-\frac{3}{5}\right)^2=x^2\end{cases}}\)

\(\Leftrightarrow\hept{\begin{cases}\frac{3}{5}=x\\-\frac{3}{5}=x\end{cases}}\)

Vậy........

=> 0,4/x = x/0,9

<=> x^2 = 0,4 . 0,9

<=> x^2 = 0,36

<=> x = 0,6 hoặc - 0,6

    (k đúng cho mk nha)

`a, 16/x = x /25`

`<=> 16 . 25 = x^2`

`<=> 400 = x^2`

`<=> x = +-20`.

`b, x/-2 = -8/x`

`<=> x^2 = (-2).(-8)`

`<=> x^2 = 16`

`<=> x = +-4`.`

c, -4/x = x/-49`

`x^2 = (-4).(-49)`

`x^2 = 196`

`x = +-14.`

`d, -x/3 = 27/-x`

`<=> (-x)^2 = 81`

`<=> x^2 = 81`

`<=> x = +-9`

Giúp e làm bài với ạ!! E cảm ơn!

a: =>x-2=6,3

=>x=8,3

d:=>|x-3|=14

=>x-3=14 hoặc x-3=-14

=>x=17 hoặc x=-11

giải nhanh giúp tui 

\(\dfrac{x}{3}=\dfrac{-10}{6}\)

\(\Leftrightarrow6x=-10.3\)

\(\Leftrightarrow6x=-30\)

\(\Leftrightarrow x=-30:6\)

\(\Leftrightarrow x=-5\)

Vậy \(x=-5\)

a) \(\dfrac{x}{3}=\dfrac{-10}{6}\)

\(x\times6=-10\times3\)

\(x\times6=-30\)

\(x=-5\)

b) \(\dfrac{-8}{x}=\dfrac{-9}{15}\)

\(x\times-9=15\times-8\)

\(x\times-9=-120\)

\(x=\dfrac{40}{3}\)

c) \(\dfrac{2,7}{0,9}=\dfrac{-8}{x}\)

\(x\times2,7=-8\times0,9\)

\(x\times2,7=-7,2\)

\(x=-\dfrac{8}{3}\)

d) \(\dfrac{4}{9}=\dfrac{x}{12}\)

\(x\times9=12\times4\)

\(x\times9=48\)

\(x=\dfrac{48}{9}\)

\(x=\dfrac{16}{3}\)