The distributive property is...
a(b + c) = ab + ac
or
a(b - c) = ab - ac
So...
root6 (root30 - 2)
= root6 x root30 - root6 x 2
= root180 - 2root6
= 6root5 - 2root6
6root5 means 6 x root5
2root6 means 2 x root6
