`11)`
\(\left\{ \begin{array}{l}2x - 5 ≥ 0\\x^2 - 4x - 5 \ne 0\end{array} \right.\)
`<=>` \(\left\{ \begin{array}{l}2x ≥ 5\\(x - 5)(x + 1) \ne 0\end{array} \right.\)
`<=>` \(\left\{ \begin{array}{l}x ≥ \dfrac{5}{2}\\x - 5 \ne 0\\x + 1 \ne 0 \end{array} \right.\)
`<=>` \(\left\{ \begin{array}{l}x ≥ \dfrac{5}{2}\\x \ne 5\\x \ne -1\end{array} \right.\)
`=> D = [5/2; +∞) \\ {5}`
`14)`
\(\left\{ \begin{array}{l}x + 3 ≥ 0\\3 - x ≥ 0\\x - 1 > 0\end{array} \right.\)
`<=>` \(\left\{ \begin{array}{l}x ≥ -3\\x ≤ 3\\x > 1\end{array} \right.\)
`=> D = (1; 3]`
