Question

giúp mình bài này với 

Answer 1

\(Q=\left(3-\dfrac{x+\sqrt{x}}{\sqrt{x}+1}\right)\left(3+\dfrac{x-\sqrt{x}}{\sqrt{x}-1}\right)\)

\(Q=\left(3-\dfrac{\sqrt{x}\left(\sqrt{x}+1\right)}{\sqrt{x}+1}\right)\left(3+\dfrac{\sqrt{x}\left(\sqrt{x}-1\right)}{\sqrt{x}-1}\right)\)

\(Q=\left(3-\sqrt{x}\right)\left(3+\sqrt{x}\right)\)

\(Q=3^2-\left(\sqrt{x}\right)^2\)

\(Q=9-x\)

Answer 2

\(Q=\left(3-\dfrac{\sqrt{x}\left(\sqrt{x}+1\right)}{\sqrt{x}+1}\right)\left(3+\dfrac{\sqrt{x}\left(\sqrt{x}-1\right)}{\sqrt{x}-1}\right)\)

=(3-căn x)(3+căn x)

=9-x

Answer 3

\(Q=\left(3-\dfrac{x+\sqrt{x}}{\sqrt{x}+1}\right)\left(3+\dfrac{x-\sqrt{x}}{\sqrt{x}-1}\right)\)

\(=\left[3-\dfrac{\sqrt{x}\left(\sqrt{x}+1\right)}{\sqrt{x}+1}\right]\left[3+\dfrac{\sqrt{x}\left(\sqrt{x}-1\right)}{\sqrt{x}-1}\right]\)

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

\(=9-x\)