Question

$( 2sqrt{20} - 5sqrt{8} -2 sqrt{5} + sqrt{18} ) * 3 sqrt{10}$

Answer 1

6√200-15√80-6√50+3√180=6*10√2-15*4√5-6*5√2+3*6√5=
=60√2-60√5-30√2+18√5=30√2-42√5