\(\Rightarrow\left[{}\begin{matrix}3^x-27=0\\2\sqrt{x}-4=0\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}3^x=27\\2\sqrt{x}=4\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x=3\\\sqrt{x}=2\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x=3\\x=4\end{matrix}\right.\)
\(\Rightarrow x\in\left(3;4\right)\)
`(3^x -27)(2sqrt{x} -4) =0`
`Đk : x in Z ; x >=0`
`=> `\(\left[{}\begin{matrix}3^x-27=0\\2\sqrt{x}-4=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}3^x=27\\2\left(\sqrt{x}-2\right)=0\end{matrix}\right.\)
`<=> [(3^x = 3^3),(sqrt{x}-2 =0):}`
`=> [(x=3),(sqrt{x}=2):}`
`=> [(x=3(t//m) ) , (x=4 (t//m) ) :}`
Vậy `x in {3;4}`
