Answer
$\dfrac{1-\sqrt{5}}{3}=-\dfrac{4}{3+3\sqrt{5}}$
Work Step by Step
$\dfrac{1-\sqrt{5}}{3}$
Multiply both numerator and denominator by $1+\sqrt{5}$ and simplify:
$\dfrac{1-\sqrt{5}}{3}=\Big(\dfrac{1-\sqrt{5}}{3}\Big)\Big(\dfrac{1+\sqrt{5}}{1+\sqrt{5}}\Big)=\dfrac{1^{2}-(\sqrt{5})^{2}}{3+3\sqrt{5}}=...$
$...=\dfrac{1-5}{3+3\sqrt{5}}=-\dfrac{4}{3+3\sqrt{5}}$