đặt kí hiệu như hình:

 còn lại chx làm :)

oke

\(P=\left(\dfrac{\sqrt{x}}{x-4}+\dfrac{1}{\sqrt{x}-2}\right):\dfrac{2}{\sqrt{x}-2}\\ =\dfrac{\sqrt{x}+\sqrt{x}+2}{\left(\sqrt{x}+2\right)\left(\sqrt{x}-2\right)}:\dfrac{2}{\sqrt{x}-2}\\ =\dfrac{2\sqrt{x}+2}{\left(\sqrt{x}+2\right)\left(\sqrt{x}-2\right)}:\dfrac{2}{\sqrt{x}-2}\\ =\dfrac{2\left(\sqrt{x}+1\right)}{\left(\sqrt{x}+2\right)\left(\sqrt{x}-2\right)}.\dfrac{\sqrt{x}-2}{2}\\ =\dfrac{\sqrt{x}+1}{\sqrt{x}+2}\) ĐK :\(x\ge0;x\ne4\)

11h

\(P=\dfrac{2\sqrt{x}}{\sqrt{x}+3}+\dfrac{\sqrt{x}+1}{\sqrt{x}-3}+\dfrac{11\sqrt{x}-3}{x-9}\\ =\dfrac{2\sqrt{x}\left(\sqrt{x}-3\right)+\left(\sqrt{x}+1\right)\left(\sqrt{x}+3\right)+11\sqrt{x}-3}{\left(\sqrt{x}+3\right)\left(\sqrt{x}-3\right)}\\ =\dfrac{2x-6\sqrt{x}+x+3\sqrt{x}+\sqrt{x}+3+11\sqrt{x}-3}{\left(\sqrt{x}+3\right)\left(\sqrt{x}-3\right)}\\ =\dfrac{3x+9\sqrt{x}}{\left(\sqrt{x}+3\right)\left(\sqrt{x}-3\right)}\\ =\dfrac{3\sqrt{x}\left(\sqrt{x}+3\right)}{\left(\sqrt{x}+3\right)\left(\sqrt{x}-3\right)}\\ =\dfrac{3\sqrt{x}}{\sqrt{x}-3}\) 

ĐK : \(x\ge0;x\ne9\)

\(P=\left(\dfrac{\sqrt{x}}{\sqrt{x}+2}+\dfrac{2}{\sqrt{x}-2}\right):\dfrac{x+4}{\sqrt{x}+2}\\ =\dfrac{\sqrt{x}\left(\sqrt{x}-2\right)+2\left(\sqrt{x}+2\right)}{\left(\sqrt{x}+2\right)\left(\sqrt{x}-2\right)}:\dfrac{x+4}{\sqrt{x}+2}\\ =\dfrac{x-2\sqrt{x}+2\sqrt{x}+4}{\left(\sqrt{x}+2\right)\left(\sqrt{x}-2\right)}:\dfrac{x+4}{\sqrt{x}+2}\\ =\dfrac{x+4}{\left(\sqrt{x}+2\right)\left(\sqrt{x}-2\right)}.\dfrac{\sqrt{x}+2}{x+4}\\ =\dfrac{1}{\sqrt{x}-2}\) ĐK : \(x\ge0;x\ne4\)

x + 35 = 105

⇔ x = 105 - 35

⇔ x = 70

\(Q=\left(\dfrac{a}{a-2\sqrt{a}}+\dfrac{a}{\sqrt{a}-2}\right):\dfrac{\sqrt{a}+1}{a-4\sqrt{a}+4}\\ =\dfrac{a+a\sqrt{a}}{\sqrt{a}\left(\sqrt{a}-2\right)}:\dfrac{\sqrt{a}+1}{\left(\sqrt{a}-2\right)^2}\\ =\dfrac{a\left(1+\sqrt{a}\right)}{\sqrt{a}\left(\sqrt{a}-2\right)}.\dfrac{\left(\sqrt{a}-2\right)^2}{\sqrt{a}+1}\\ =\sqrt{a}\left(\sqrt{a}-2\right)\)

\(A=2\sqrt{3}-\sqrt{27}+\dfrac{3-\sqrt{3}}{\sqrt{3}}\\ =2\sqrt{3}-3\sqrt{3}+\left(\sqrt{3}-1\right)\\ =-\sqrt{3}+\sqrt{3}-1\\ =-1\)