Question

Tìm x biết

\(\left|2x-1\right|\)=2x

\(\left|x-3\right|-\left|4-x\right|=0\)

\(\left|x\right|+\left|x-2\right|=2\)

tìm GTNN của A=\(\left|x-5\right|+\left|x-2\right|\)

mk cần gấp ( lm đc câu nào thì giúp mk . mk tick cho )

Answer 1

1/

a/ \(\left|2x-1\right|=2x\)

\(\Leftrightarrow\left[{}\begin{matrix}2x-1=2x\\2x-1=-2x\end{matrix}\right.\)

\(\Leftrightarrow\left[{}\begin{matrix}2x-2x=1\left(loại\right)\\2x+2x=1\end{matrix}\right.\)

\(\Leftrightarrow4x=1\)

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

Vậy ......

b/ \(\left|x-3\right|-\left|4-x\right|=0\)

\(\Leftrightarrow\left|x-3\right|=\left|4-x\right|\)

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

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

\(\Leftrightarrow\left[{}\begin{matrix}2x=7\\0x=-1\left(loại\right)\end{matrix}\right.\)

\(\Leftrightarrow x=\dfrac{7}{2}\)

Vậy ....

Answer 2

a. \(\left|2x-1\right|=2x\Rightarrow\left[{}\begin{matrix}2x-1=2x\\2x-1=-2x\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}2x-2x=-1\\2x+2x=1\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x\in\varnothing\\x=\dfrac{1}{4}\end{matrix}\right.\)

Vậy \(x=\dfrac{1}{4}\)

Mk đang bận chiều mk làm cho bn nhé