Question

|x-3|=4x+8

Answer 1

\(\left|x-3\right|=4x+8\)

\(\Leftrightarrow\left[{}\begin{matrix}x-3=4x+8;x\ge3\\3-x=4x+8;x< 3\end{matrix}\right.\) \(\Leftrightarrow\left[{}\begin{matrix}3x=-11\\5x=-5\end{matrix}\right.\) \(\Leftrightarrow\left[{}\begin{matrix}x=-\dfrac{11}{3}\left(ktm\right)\\x=-1\left(tm\right)\end{matrix}\right.\)

Vậy \(S=\left\{-1\right\}\)

Answer 2

|x-3|=4x+8

\(\Leftrightarrow\left[{}\begin{matrix}x-3=4x+8\\x-3=-4x-8\end{matrix}\right.\)

\(\Leftrightarrow\left[{}\begin{matrix}x-3-4x-8=0\\x-3+4x+8=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}-3x=11\\5x=-5\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=-\dfrac{11}{3}\\x=-1\end{matrix}\right.\)

Answer 3

\(\left|x-3\right|=4x+8\)

\(\Leftrightarrow\left[{}\begin{matrix}-x+3=4x+8\\x-3=4x+8\end{matrix}\right.\)

\(\Leftrightarrow\left[{}\begin{matrix}x=-1\\x=-\dfrac{11}{3}\end{matrix}\right.\)

Answer 4

Cho anh thêm:

\(đk:4x+8\ge0\)

\(\Leftrightarrow x\ge-2\)

Answer 5