How do you simplify 5sqrt3(sqrt3-2)+sqrt3(7-sqrt3)?

$12 - 3 \sqrt{3}$
$5 \sqrt{3} \left(\sqrt{3} - 2\right) + \sqrt{3} \left(7 - \sqrt{3}\right)$
$= 5 {\sqrt{3}}^{2} - 5 \sqrt{3} \times 2 + 7 \sqrt{3} - {\sqrt{3}}^{2}$
$= 5 \times 3 - 10 \sqrt{3} + 7 \sqrt{3} - 3$
$= 15 - 10 \sqrt{3} + 7 \sqrt{3} - 3$
$= 12 - 3 \sqrt{3}$