giúp mik vs mn ơi hơi nhoe mn thông cảm !!!

`a)` $\dfrac{\sqrt{a}-3}{a-9}$

`=` $\dfrac{\sqrt{a}-3}{(\sqrt{a}-3)(\sqrt{a}+3)}$

`=` $\dfrac{1}{\sqrt{a}+3}$

`b)` $\dfrac{a-2\sqrt{a}+1}{\sqrt{a}-1}$

`=` $\dfrac{(\sqrt{a}-1)²}{\sqrt{a}-1}$

`=` $sqrt{a}$ `- 1`

`c)` $\dfrac{a-4\sqrt{a}+4}{4-a}$

`= -` $\dfrac{(\sqrt{a}-2)²}{a-4}$

`= -` $\dfrac{(\sqrt{a}-2)²}{(\sqrt{a}-2)(\sqrt{a}+2)}$

`= -` $\dfrac{\sqrt{a}-2}{\sqrt{a}+2}$

`d)` $\dfrac{x-5\sqrt{x}+6}{\sqrt{x}-3}$

`=` $\dfrac{(\sqrt{x}-2)(\sqrt{x}-3)}{\sqrt{x}-3}$

`=` $\sqrt{x}$ `- 2`

`e)` $\dfrac{x²+2\sqrt{2}x+2}{x²-2}$

`=` $\dfrac{(x+\sqrt{2})²}{(x-\sqrt{2})(x+\sqrt{2})}$

`=` $\dfrac{x+\sqrt{2}}{x-\sqrt{2}}$