Answer
$=-\sqrt{3}$.
Work Step by Step
The given expression is
$=5\sqrt{27}-4\sqrt{48}$
Factor the radicands:
$=5\sqrt{3^2\cdot3}-4\sqrt {4^2\cdot 3}$
$=5\cdot3\sqrt{3}-4\cdot 4\sqrt { 3}$
$=15\sqrt{3}-16\sqrt { 3}$
By using the distributive property:
$=(15-16)\sqrt{3}$
Simplify.
$=-\sqrt{3}$.
