Question

giúp em bài 8 với ạ, em cảm ơn

Answer 1

Bài 4:

\(x-\sqrt{2x+3}=0\) (ĐK: \(x\ge-\dfrac{3}{2}\))

\(\Leftrightarrow x=\sqrt{2x+3}\)

\(\Leftrightarrow x^2=2x+3\)

\(\Leftrightarrow x^2-2x-3=0\)

\(\Leftrightarrow\left(x-3\right)\left(x+1\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x-3=0\\x+1=0\end{matrix}\right.\)

\(\Leftrightarrow\left[{}\begin{matrix}x=3\left(tm\right)\\x=-1\left(tm\right)\end{matrix}\right.\)