Đáp án:
Giải thích các bước giải:
2) `B=\frac{\sqrt{x}-1}{\sqrt{x}-3}+\frac{7\sqrt{x}-9}{9-x}`
`B=\frac{(\sqrt{x}-1)(\sqrt{x}+3)}{(\sqrt{x}-3)(\sqrt{x}+3)}-\frac{7\sqrt{x}-9}{(\sqrt{x}-3)(\sqrt{x}+3)}`
`B=\frac{x+2\sqrt{x}-3-7\sqrt{x}+9}{(\sqrt{x}-3)(\sqrt{x}+3)}`
`B=\frac{x-5\sqrt{x}+6}{(\sqrt{x}-3)(\sqrt{x}+3)}`
`B=\frac{(\sqrt{x}-2)(\sqrt{x}-3)}{(\sqrt{x}-3)(\sqrt{x}+3)}`
`B=\frac{\sqrt{x}-2}{\sqrt{x}+3}`
`P=\frac{A}{B}`
`P=\frac{\sqrt{x}-2}{\sqrt{x}}:\frac{sqrt{x}-2}{\sqrt{x}+3}`
`P=frac{\sqrt{x}+3}{\sqrt{x}}`
