Question

Bài 1:Rút gọn A=(2√x/√-3 +x/3√x-x):√+3/x-9

Bài 2:Rút gọn B=(2+√x/√x - √x/√x-2):4√x-4/x-2√x

Bài 3:Cho P=√x+2/√x+3 - 5/x+√x-6 - 1/√-2

a)Rút gọn P

b)Tính P khi x=6+4√2

Cứuuuu

Answer 1

Bài 1:

Ta có: \(A=\left(\frac{2\sqrt{x}}{\sqrt{x}-3}+\frac{x}{3\sqrt{x}-x}\right):\frac{\sqrt{x}+3}{x-9}\)

\(=\left(\frac{2x}{\sqrt{x}\left(\sqrt{x}-3\right)}-\frac{x}{\sqrt{x}\left(\sqrt{x}-3\right)}\right):\frac{\sqrt{x}+3}{\left(\sqrt{x}+3\right)\left(\sqrt{x}-3\right)}\)

\(=\frac{x}{\sqrt{x}\left(\sqrt{x}-3\right)}:\frac{1}{\sqrt{x}-3}\)

\(=\frac{x\cdot\left(\sqrt{x}-3\right)}{\sqrt{x}\cdot\left(\sqrt{x}-3\right)}\)

\(=\sqrt{x}\)