Question

Giải phương trình

|4x-1| = x+2

 

Answer 1

-ĐK\(x+2\ge0\Leftrightarrow x\ge-2\): 

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

-Vậy \(S=\left\{1\right\}\)

Answer 2

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