How do you simplify (5-4sqrt5)(-2+sqrt5)?

Jun 5, 2018

$- 30 + 13 \sqrt{5}$
$- 10 + 5 \sqrt{5} + 8 \sqrt{5} - 4 \sqrt{25}$
$- 10 + 13 \sqrt{5} - 20$
$- 30 + 13 \sqrt{5}$