`\text{~~Holi~~}`
`a. y=3+\sqrt{2x-1}`
`->`\(\left[ \begin{array}{l}3\\\sqrt{2x-1}\\2x-1\end{array} \right.\)
`->`\(\left[ \begin{array}{l}x∈R\\x\geq \frac{1}{2}\\x∈R\end{array} \right.\)
`-> x∈[1/2, +∞)`
`b. y=(x+2)/(1-5x)`
`-> y=(x+2)/(-5x+1)`
`->` \(\left[ \begin{array}{l}\frac{x+2}{-5x+1}\\x+2\\-5x+1\end{array} \right.\)
`->` \(\left[ \begin{array}{l}x∈R \ {{\frac{1}{5}}}\\x∈R\\x∈R\end{array} \right.\)
`-> x∈R\{1/5}`