Question

giúp e bài 4 ạ

Answer 1

Bài 2: 

a: Ta có: \(5\sqrt{x+5}-\sqrt{9x+45}+\sqrt{4x+20}-12=0\)

\(\Leftrightarrow5\sqrt{x+5}-3\sqrt{x+5}+2\sqrt{x+5}=12\)

\(\Leftrightarrow x+5=9\)

hay x=4

b: Ta có: \(\sqrt{x^2-6x+9}+4=6\)

\(\Leftrightarrow\left|x-3\right|=2\)

\(\Leftrightarrow\left[{}\begin{matrix}x-3=2\\x-3=-2\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=5\\x=1\end{matrix}\right.\)