Question

Answer 1

\(P=\dfrac{x+7}{3\sqrt{x}}\)

Khi x=4

⇒ \(P=\dfrac{4+7}{3\sqrt{4}}\)

        \(=\dfrac{11}{3.2}=\dfrac{11}{6}\)

Answer 2

a) \(P=\dfrac{4+7}{3\sqrt{4}}=\dfrac{11}{3.2}=\dfrac{11}{6}\)

b) \(Q=\dfrac{\left(\sqrt{x}+1\right)\left(\sqrt{x}+3\right)+2\sqrt{x}\left(\sqrt{x}-3\right)-7\sqrt{x}-3}{\left(\sqrt{x}-3\right)\left(\sqrt{x}+3\right)}\)

\(=\dfrac{3x-9\sqrt{x}}{\left(\sqrt{x}-3\right)\left(\sqrt{x}+3\right)}=\dfrac{3\sqrt{x}\left(\sqrt{x}-3\right)}{\left(\sqrt{x}-3\right)\left(\sqrt{x}+3\right)}=\dfrac{3\sqrt{x}}{\sqrt{x}+3}\)