Question

tìm số hữu tỉ x biết: \(x-2\sqrt{x}=0\left(x\ge0\right)\))

Answer 1

x - 2\(\sqrt{x}\) = 0

<=> \(\sqrt{x}\)(\(\sqrt{x}\)- 2) = 0

<=> x = 0 hoặc x = 4

Answer 2

\(x-2\sqrt{x}=0\)

\(\Leftrightarrow\sqrt{x}^2-2\sqrt{x}=0\)

\(\Leftrightarrow\sqrt{x}\left(\sqrt{x}-2\right)=0\)

\(\Rightarrow\orbr{\begin{cases}\sqrt{x}=0\\\sqrt{x}-2=0\end{cases}\Rightarrow\orbr{\begin{cases}x=0\\\sqrt{x}=2\end{cases}\Rightarrow}\orbr{\begin{cases}x=0\\x=4\end{cases}}}\)