Ta lập bảng xét dấu:

+) Nếu x < 1 thì \(\left\{{}\begin{matrix}\left|x-1\right|=-x+1\\\left|2x-4\right|=-2x+4\end{matrix}\right.\)

Do đó: \(\left|x-1\right|+\left|2x-4\right|=3x\)

\(\Leftrightarrow\left(-x+1\right)+\left(-2x+4\right)=3x\)

\(\Leftrightarrow-x+1-2x+4=3x\)

\(\Leftrightarrow\left(-x-2x\right)+\left(1+4\right)=3x\)

\(\Leftrightarrow-3x+5=3x\)

\(\Leftrightarrow3x+3x=5\)

\(\Leftrightarrow6x=5\)

\(\Leftrightarrow x=\dfrac{5}{6}\)(Thỏa mãn)

+) Nếu \(1< x< 2\) thì \(\left\{{}\begin{matrix}\left|x-1\right|=x-1\\\left|2x-4\right|=-2x+4\end{matrix}\right.\)

Do đó: \(\left|x-1\right|+\left|2x-4\right|=3x\)

\(\Leftrightarrow\left(x-1\right)+\left(-2x+4\right)=3x\)

\(\Leftrightarrow x-1-2x+4=3x\)

\(\Leftrightarrow\left(x-2x\right)+\left(-1+4\right)=3x\)

\(\Leftrightarrow-x+3=3x\)

\(\Leftrightarrow3x+x=3\)

\(\Leftrightarrow4x=3\)

\(\Leftrightarrow x=\dfrac{3}{4}\) (k thỏa mãn nên loại)

+) Nếu \(x>2\) thì: \(\left\{{}\begin{matrix}\left|x-1\right|=x-1\\\left|2x-4\right|=2x-4\end{matrix}\right.\)

Do đó: \(\left|x-1\right|+\left|2x-4\right|=3x\)

\(\Leftrightarrow\left(x-1\right)+\left(2x-4\right)=3x\)

\(\Leftrightarrow x-1+2x-4=3x\)

\(\Leftrightarrow\left(x-2x\right)+\left(-1-4\right)=3x\)

\(\Leftrightarrow-x-5=3x\)

\(\Leftrightarrow2x=5\)

\(\Rightarrow x=\dfrac{5}{2}\) (thỏa mãn). Vậy \(\left[{}\begin{matrix}x=\dfrac{2}{3}\\x=\dfrac{5}{2}\end{matrix}\right.\)

Số nghịch đảo của : \(\dfrac{4}{5}=\dfrac{5}{4};-3=\dfrac{-1}{3};\dfrac{-4}{7}=\dfrac{-7}{4};\dfrac{2}{-5}=\dfrac{-5}{2};123=\dfrac{1}{123}\)

bằng 10.

- if that people is a kid, i love Thien Nhan. Becau she has a sweet voice and she look very cute with a long black hair.

- if that people is a adult, i love Noo Phuoc Thinh. Becau he has a warm voice. He very handsome, good at music and famous. When he smile, my heart started to stops beating.

That so!!!

- In my life, my idol is very important. He is a cute boy. When he sad, i will sad with him. I often share with him many things. Do you know who is he?