\(\dfrac{5\left(x-3\right)}{\sqrt{x}+\sqrt{3}}\)
Điều kiện: \(x\ge0;x\ne3\)
\(\dfrac{5\left(x-3\right)}{\sqrt{x}+\sqrt{3}}=\dfrac{5\left(x-3\right).\left(\sqrt{x}-3\right)}{\left(\sqrt{x}+3\right)\left(\sqrt{x}-3\right)}\)
\(=\dfrac{5\left(x-3\right)\left(\sqrt{x}+\sqrt{3}\right)}{x-3}\)
\(=5\left(\sqrt{x}+\sqrt{3}\right)\)