Question

How to simplify my answer

Answer 1

Assuming that dot means multiply

remember
$(\frac{a}{b})(\frac{c}{d})=\frac{ac}{bd}$

so
remember that it is helpful to factor them to simplify

$(\frac{x-5}{3x+12})(\frac{2x+8}{2x-10})=$
$\frac{(x-5)(2x+8)}{(3x+12)(2x-10)}=$
$\frac{(x-5)(2)(x+4)}{(3)(x+4)(2)(x-5)}=$
$(\frac{(x-5)(2)(x+4)}{(x-5)(2)(x+4)})(\frac{1}{3})=$
$(1)(\frac{1}{3}=$
$\frac{1}{3}$