Đáp án:
Giải thích các bước giải:
a)p=$\frac{\sqrt{x} }{\sqrt{x}-1}$ +$\frac{3}{\sqrt{x}+1}$+ $\frac{6x-4}{1-x}$
=$\frac{\sqrt{x}(\sqrt{x}+1) +3(\sqrt{x}-1)-(6x-4)}{(\sqrt{x}-1)(\sqrt{x}+1)}$
=$\frac{x+\sqrt{x}+3\sqrt{x}-3-6x+4}{(\sqrt{x}-1)(\sqrt{x}+1)}$
=$\frac{4\sqrt{x}-5x+1}{(\sqrt{x}-1)(\sqrt{x}+1)}$ $\frac{-5x+5\sqrt{x}-\sqrt{x}+1}{(\sqrt{x}-1)(\sqrt{x}+1)}$ $\frac{-5\sqrt{x}(\sqrt{x}+1)-(\sqrt{x}+1)}{(\sqrt{x}-1)(\sqrt{x}+1)}$ $\frac{(\sqrt{x}+1)(-5\sqrt{x}-1)}{(\sqrt{x}-1)(\sqrt{x}+1)}$ $\frac{-5\sqrt{x}-1}{\sqrt{x}-1}$
b)x=7-4$\sqrt[]{3}$ =(2-$\sqrt[]{3}$ )²
thay x=(2-$\sqrt[]{3}$ )² vào P ta dc
$\frac{-5\sqrt[]{(2-\sqrt[]{3} )²} }{\sqrt[]{(2-\sqrt[]{3})²}-1 }$=$\frac{-5+5\sqrt[]{3} }{2}$
