các bạn giúp mik bài này vs mik đang cần gấp
\(1,A=\dfrac{4+1}{4-3}=5\\ 2,P=\dfrac{A}{B}=\dfrac{\sqrt{a}+1}{\sqrt{a}-3}:\dfrac{2a-6\sqrt{a}+a+3\sqrt{a}-3a-3}{\left(\sqrt{a}-3\right)\left(\sqrt{a}+3\right)}\\ P=\dfrac{\sqrt{a}+1}{\sqrt{a}-3}\cdot\dfrac{\left(\sqrt{a}-3\right)\left(\sqrt{a}+3\right)}{-3\left(\sqrt{a}+1\right)}=\dfrac{-\sqrt{a}-3}{3}\\ 3,P=\dfrac{-\sqrt{a}-3}{3}=-1-\dfrac{\sqrt{a}}{3}\le0< 1\)