a. \(x=\pm3\) e. \(\left[{}\begin{matrix}x>3\\x< -3\end{matrix}\right.\)
b. x=1
c. \(-2\le x\le2\)
h. \(x\le-3\) k. \(\left[{}\begin{matrix}x\ge-2\\x\le2\end{matrix}\right.\)
a) Ta có: \(\left|x\right|=3\)
\(\Leftrightarrow\left[{}\begin{matrix}x=3\\x=-3\end{matrix}\right.\)
Vậy: S={3;-3}
b) Ta có: \(\left|x-1\right|=0\)
\(\Leftrightarrow x-1=0\)
\(\Leftrightarrow x=1\)
Vậy: S={1}
c) Ta có: \(\left|x\right|\le2\)
\(\Leftrightarrow-2\le x\le2\)
Vậy: S={x|\(-2\le x\le2\)}
d) Ta có: \(\left|x+3\right|\le0\)
\(\Leftrightarrow x+3=0\)
\(\Leftrightarrow x=-3\)
Vậy: S={-3}
e) Ta có: \(\left|x\right|>3\)
\(\Leftrightarrow\left[{}\begin{matrix}x>3\\x< -3\end{matrix}\right.\)
Vậy: S={x|x>3 hoặc x<-3}
k) Ta có: \(\left|x+2\right|\ge0\)
mà \(\left|x+2\right|\ge0\forall x\)
nên \(x\in R\)
Vậy: S={x|\(x\in R\)}
