Question

Answer 1

\(1,\\ a,ĐK:x\ge2\\ PT\Leftrightarrow4x-8=4\Leftrightarrow x=3\left(tm\right)\\ b,ĐK:x\ge-8\\ PT\Leftrightarrow\dfrac{1}{2}x+4=\dfrac{4}{9}\Leftrightarrow x=-\dfrac{64}{9}\left(tm\right)\\ c,ĐK:x\ge\dfrac{9}{5}\\ PT\Leftrightarrow5x-9=1\Leftrightarrow x=2\left(tm\right)\)

Answer 2

Bài 2: 

c: Ta có: \(C=\dfrac{\sqrt{x}+2}{\sqrt{x}-2}+\dfrac{\sqrt{x}-2}{\sqrt{x}+2}-\dfrac{2x+9}{x-4}\)

\(=\dfrac{x+4\sqrt{x}+4+x-4\sqrt{x}+4-2x-9}{x-4}\)

\(=\dfrac{-1}{x-4}\)