`a) ĐKXĐ: x >= 0`
`b) ĐKXĐ:`
\(\left\{ \begin{array}{l}x ≥ 0\\x + 2\sqrt{x} + 3 \ne 0\end{array} \right.\)
`->` \(\left\{ \begin{array}{l}x ≥ 0\\(\sqrt{x} + 1)^2 + 2 \ne 0\end{array} \right.\)
`-> x ≥ 0`
`c) ĐKXĐ:`
\(\left\{ \begin{array}{l}x + 1 ≥ 0\\x - 2 > 0\end{array} \right.\)
`->` \(\left\{ \begin{array}{l}x ≥ -1\\x > 2\end{array} \right.\)
`-> x > 2`
`d) ĐKXĐ:`
\(\left\{ \begin{array}{l}x ≥ 0\\x \ne 1\end{array} \right.\)