Answer
$-6-3\sqrt 5$
Work Step by Step
Multiply by the conjugate radical of the denominator:
$\frac{3}{2-\sqrt 5}\times\frac{2+\sqrt 5}{2+\sqrt 5}$
Simplify using Special Product Formula 1:
$3\times\frac{2+\sqrt 5}{(2)^2-(\sqrt 5)^2}=\frac{6+3\sqrt 5}{-1}=−6−3\sqrt 5$