Question

tìm x,biết

\(\left|2x-5\right|=3\)

Answer 1

\(\left|2x-5\right|=3\)

\(\Rightarrow\left[{}\begin{matrix}2x-5=3\\2x-5=-3\end{matrix}\right.\)\(\Rightarrow\left[{}\begin{matrix}2x=2+5\\2x=-3+5\end{matrix}\right.\)\(\Rightarrow\left[{}\begin{matrix}x=\dfrac{7}{2}\\x=\dfrac{2}{2}=1\end{matrix}\right.\)

vậy \(\left[{}\begin{matrix}x=\dfrac{7}{2}\\x=1\end{matrix}\right.\)

Answer 2

Ta có: |2x - 5| = 3

=> 2x - 5 = 3 hoặc 2x - 5 = -3

+/ 2x - 5 = 3

=> 2x = 3 + 5 = 8

=> x = 8/2 = 4

+/ 2x - 5 = -3

=> 2x = -3 + 5 = 2

=> x = 2/2 = 1.

Vậy x thuộc {4;1}

P/s: Đây là toán lớp 10 sao??