Question

[Nguyễn Thanh Hằng]

Câu 6 : tìm x:

a) x+1/2016-x+2/2015=x+2017/2014

b) 5 - |3x - 1|= 3

c) (1 - 2x)²= 9

Answer 1

[Nguyễn Lê Phước Thịnh]

b) Ta có: \(5-\left|3x-1\right|=3\)

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

\(\Leftrightarrow\left[{}\begin{matrix}3x-1=-2\\3x-1=2\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}3x=-1\\3x=3\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\frac{-1}{3}\\x=1\end{matrix}\right.\)

Vậy: \(x\in\left\{-\frac{1}{3};1\right\}\)

c) Ta có: \(\left(1-2x\right)^2=9\)

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

Vậy: \(x\in\left\{-1;2\right\}\)