Answer: 3*(√5+√2).
Step-by-step explanation:
[tex]\boxed {(a-b)*(a+b)=a^2-b^2}[/tex]
[tex]\displaystyle\\\frac{9}{\sqrt{5}-\sqrt{2} } =\\\\\frac{9*(\sqrt{5}+\sqrt{2}) }{(\sqrt{5}-\sqrt{2})*(\sqrt{5}+\sqrt{2)} } =\\\\\frac{9*(\sqrt{5}+\sqrt{2}) }{(\sqrt{5})^2-(\sqrt{2})^2} } =\\\\\frac{9*(\sqrt{5}+\sqrt{2}) }{5-2 } =\\\\\frac{9*(\sqrt{5}+\sqrt{2}) }{3 } =\\\\3*(\sqrt{5}+\sqrt{2}).[/tex]
