#### Answer

$= -\frac{1}{2} $

#### Work Step by Step

$\frac{2(x-4)}{4x+20} \times \frac{3(x+5)}{12-3x}$
$= \frac{2(x-4)}{4(x+5)} \times \frac{3(x+5)}{3(4-x)}$
$= \frac{6(x-4)(x+5)}{12(x+5)(4-x)} $
$= \frac{6(x-4)(x+5)}{12(x+5)(-(x-4))} $
$= \frac{6(x+5)}{-12(x+5)} $
$= -\frac{6(x+5)}{12(x+5)} $
$= -\frac{6}{12} $
$= -\frac{1}{2} $