Question

[Trang Ngọc]

Tìm số x không âm, biết a) √x (√x-1)?= 0 b) (√x-2) (√x+3) = 0 c) (√x +1) (√x+2) = 0

Answer 1

[Lê Song Phương]

a) \(\sqrt{x}\left(\sqrt{x}-1\right)=0\Leftrightarrow\orbr{\begin{cases}\sqrt{x}=0\\\sqrt{x}-1=0\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=0\\x=1\end{cases}}\)

b) \(\left(\sqrt{x}-2\right)\left(\sqrt{x}+3\right)=0\Leftrightarrow\orbr{\begin{cases}\sqrt{x}-2=0\\\sqrt{x}+3=0\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=4\\\sqrt{x}=-3\left(vôlí\right)\end{cases}}\)

c) \(\left(\sqrt{x}+1\right)\left(\sqrt{x}+3\right)=0\Leftrightarrow\orbr{\begin{cases}\sqrt{x}+1=0\\\sqrt{x}+3=0\end{cases}}\Leftrightarrow\orbr{\begin{cases}\sqrt{x}=-1\left(vôlí\right)\\\sqrt{x}=-3\left(vôlí\right)\end{cases}}\)