a) ĐKXĐ:
x - 2 > 0
\(\Leftrightarrow x>2\)
b) \(\sqrt{4x^2-4x+1}=\sqrt{\left(2x-1\right)^2}\)
Do \(\left(2x-1\right)^2\ge0\) với mọi \(x\in R\)
Vậy ĐKXĐ: với mọi \(x\in R\)
c) \(\sqrt{x^2-x-6}=\sqrt{\left(x-3\right)\left(x+2\right)}\)
ĐKXĐ:
\(\left[{}\begin{matrix}\left\{{}\begin{matrix}x-3\ge0\\x+2\ge0\end{matrix}\right.\\\left\{{}\begin{matrix}x-3< 0\\x+2< 0\end{matrix}\right.\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}\left\{{}\begin{matrix}x\ge3\\x\ge-2\end{matrix}\right.\\\left\{{}\begin{matrix}x< 3\\x< -2\end{matrix}\right.\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x\ge3\\x< -2\end{matrix}\right.\)
d) ĐKXĐ:
x - 1 < 0
\(\Leftrightarrow x< 1\)
