#### Answer

$=-\frac{10(b-4)}{3(b+4)} $

#### Work Step by Step

$\frac{8b-10}{3b+12} \div \frac{5-4b}{5b-20}$
$=\frac{8b-10}{3b+12} \times \frac{5b-20}{5-4b}$
$=\frac{2(4b-5)}{3(b+4)} \times \frac{5(b-4)}{-(4b-5)}$
$=\frac{2}{3(b+4)} \times \frac{5(b-4)}{-1}$
$=-\frac{10(b-4)}{3(b+4)} $