Question

giúp mình ý 3 với 

Answer 1

3: P=A*B

\(=\dfrac{2\sqrt{x}+5}{\sqrt{x}-1}\cdot\dfrac{\sqrt{x}-1}{\sqrt{x}+3}\)

\(=\dfrac{2\sqrt{x}+5}{\sqrt{x}+3}\)

\(P-1=\dfrac{2\sqrt{x}+5-\sqrt{x}-3}{\sqrt{x}+3}=\dfrac{\sqrt{x}+2}{\sqrt{x}+3}>0\)

=>P>1

=>\(P>\sqrt{P}\)