Question

giúp mình với 

Answer 1

ai đó giúp mình đi huhu TT

Answer 2

\(a,A=\dfrac{4\cdot5}{5+3}=\dfrac{20}{8}=\dfrac{5}{2}\\ b,B=\dfrac{2\sqrt{x}-6+x+3\sqrt{x}+\sqrt{x}+15}{\left(\sqrt{x}+3\right)\left(\sqrt{x}-3\right)}=\dfrac{x+6\sqrt{x}+9}{\left(\sqrt{x}-3\right)\left(\sqrt{x}+3\right)}\\ B=\dfrac{\left(\sqrt{x}+3\right)^2}{\left(\sqrt{x}-3\right)\left(\sqrt{x}+3\right)}=\dfrac{\sqrt{x}+3}{\sqrt{x}-3}\\ c,P=AB=\dfrac{4\sqrt{x}}{\sqrt{x}-3}< 0\Leftrightarrow\sqrt{x}-3< 0\Leftrightarrow0\le x< 9\)

Answer 3

Answer 4