Question

Tìm x :

/x-5/ = /2x-1/

/x-7/ = -5

 

 

Answer 1

a) Ta có: |x-5|=|2x-1|

\(\Leftrightarrow\left[{}\begin{matrix}x-5=2x-1\\x-5=1-2x\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x-2x=-1+5\\x+2x=1+5\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}-x=4\\3x=6\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=-4\\x=2\end{matrix}\right.\)

Vậy: \(x\in\left\{-4;2\right\}\)

b) Vì |x-7| luôn dương

nên Khi |x-7|=-5 thì x∈∅

Vậy: x∈∅