[toán 9] rút gọn biểu thức

P

pinkylun

$P=\dfrac{(x\sqrt{x}-1)(\sqrt{x}+1)-(x\sqrt{x}+1)(\sqrt{x}-1)+(x+1)(x-1)}{\sqrt{x}(\sqrt{x}-1)(\sqrt{x}+1)}$

$P=\dfrac{2x^2-2+x^2-1}{x\sqrt{x}-\sqrt{x}}$

$P=\dfrac{3(x-1)(x+1)}{\sqrt{x}(x-1)}$

$P=\dfrac{3x+3}{\sqrt{x}}$

$P=\dfrac{9}{2}<=>\dfrac{3x+3}{\sqrt{x}}=\dfrac{9}{2}$

$<=>3(x+1)=\dfrac{9}{2}\sqrt{x}$

$<=>9(x+1)^2=\dfrac{81}{4}x$

$=>.....$
 
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