Câu 1:
`1/(x\sqrt{2x - 1})`
`ĐK:`
\(\left\{ \begin{array}{l}x \ne 0\\2x - 1 > 0\end{array} \right.\)
`->` \(\left\{ \begin{array}{l}x \ne 0\\x > \dfrac{1}{2}\end{array} \right.\)
`-> D = (1/2; +infty)`
Câu 2:
Ta có:
`y (-x)`
`= (|-(x + 7)| + |-(x - 7)|)/(|-(2x + 3)| - |-(2x - 3)|)`
`= (|x + 7| + |x - 7|)/(|2x + 3| - |2x - 3|)`
`= - y`
`->` hàm số lẻ