# How do you simplify 4sqrt125 - 5sqrt5?

You can write it as $15 \sqrt{5}$
$4 \sqrt{5 \cdot 25} - 5 \sqrt{5} = 4 \sqrt{5} \sqrt{25} - 5 \sqrt{5} = 4 \cdot 5 \sqrt{5} - 5 \sqrt{5} =$
$= 20 \sqrt{5} - 5 \sqrt{5} = 15 \sqrt{5}$