Answer
$\displaystyle \frac{-6}{7-\sqrt{5}}=\frac{-42-6\sqrt{5}}{44}$
Work Step by Step
$\displaystyle \frac{-6}{7-\sqrt{5}}\qquad$ ...rationalize the denominator by multiplying it with its conjugate, $7+\sqrt{5}$.
$=\displaystyle \frac{-6}{7-\sqrt{5}}\cdot\frac{7+\sqrt{5}}{7+\sqrt{5}}\qquad$ ...simplify.
$=\displaystyle \frac{-42-6\sqrt{5}}{49+7\sqrt{5}-7\sqrt{5}-5}\qquad$ ...simplify the denominator.
$=\displaystyle \frac{-42-6\sqrt{5}}{44}$
