Question

mn giúp mik câu c vs ạ

Answer 1

\(B=\dfrac{\sqrt{x}}{\sqrt{x}-2}\Rightarrow C=\dfrac{x+3}{\sqrt{x}}=\sqrt{x}+\dfrac{3}{\sqrt{x}}\ge2\sqrt{\dfrac{3\sqrt{x}}{\sqrt{x}}}=2\sqrt{3}\)

Dấu "=" xảy ra khi \(\sqrt{x}=\dfrac{3}{\sqrt{x}}\Rightarrow x=3\)