#### Answer

$\dfrac{2-\sqrt{7}}{-5}=\dfrac{3}{5(2+\sqrt{7})}$

#### Work Step by Step

$\dfrac{2-\sqrt{7}}{-5}$
Multiply the numerator and the denominator of this expression by the conjugate of the numerator and simplify if possible:
$\dfrac{2-\sqrt{7}}{-5}=\dfrac{2-\sqrt{7}}{-5}\cdot\dfrac{2+\sqrt{7}}{2+\sqrt{7}}=\dfrac{2^{2}-(\sqrt{7})^{2}}{-5(2+\sqrt{7})}=...$ $...=\dfrac{4-7}{-5(2+\sqrt{7})}=\dfrac{-3}{-5(2+\sqrt{7})}=\dfrac{3}{5(2+\sqrt{7})}$