ĐKXĐ: $\begin{cases} x+9\ge 0 \\ x+6\ge 0 \\\end{cases} $ `<=>` $\begin{cases} x\ge -9 \\ x\ge -6\\\end{cases}$
`=> x\ge -6`
`\sqrt{x+9}+2012\sqrt{x+6}=2012+\sqrt{(x+6)(x+9)}`
`<=> \sqrt{x+9}+2012\sqrt{x+6}-2012-\sqrt{(x+6)(x+9)}=0`
`<=> \sqrt{x+9}(1-\sqrt{x+6})-2012(1-\sqrt{x+6)=0`
`<=> (\sqrt{x+9}-2012)(1-\sqrt{x+6})=0`
`<=>`\(\left[ \begin{array}{l}\sqrt{x+9}-2012=0\\1-\sqrt{x+6}=0\end{array} \right.\)
`<=>`\(\left[ \begin{array}{l}x+9=2012^2\\1=x+6\end{array} \right.\)
`<=>` \(\left[ \begin{array}{l}x=4048135(tm)\\x=-5(tm)\end{array} \right.\)
Vậy `S={4048135; -5}`
