rút gọn
\(M=\left(1-\dfrac{\sqrt{a}}{1+\sqrt{a}}\right):\left(\dfrac{\sqrt{a}+3}{\sqrt{a}-2}+\dfrac{\sqrt{a}+2}{3-\sqrt{a}}+\dfrac{\sqrt{a}+2}{a-5\sqrt{a}+6}\right)\)
\(M=\left[\dfrac{\left(1+\sqrt{a}\right)-\sqrt{a}}{1+\sqrt{a}}\right]:\left[\dfrac{\left(\sqrt{a}+3\right)\left(\sqrt{a}-3\right)}{\left(\sqrt{a}-2\right)\left(\sqrt{a}-3\right)}-\dfrac{\left(\sqrt{a}+2\right)\left(\sqrt{a}-2\right)}{\left(\sqrt{a}-2\right)\left(\sqrt{a}-3\right)}+\dfrac{\sqrt{a}+2}{\left(\sqrt{a}-3\right)\left(\sqrt{a}-2\right)}\right]\)
\(M=\dfrac{1}{1+\sqrt{a}}:\dfrac{a-9-a+4+\sqrt{a}+2}{\left(\sqrt{a}-2\right)\left(\sqrt{a}-3\right)}\)
\(M=\dfrac{1}{\sqrt{a}+1}:\dfrac{\sqrt{a}-3}{\left(\sqrt{a}-2\right)\left(\sqrt{a}-3\right)}\)
\(M=\dfrac{\sqrt{a}-2}{\sqrt{a}+1}\)
