1) (2n-3n) (5m+n)-10(m+n)²=
2) (2√x-√y)²+4√xy=

1)(2n-3n)(5m+n)-10(m+n)²=-n(5m+n)-10(m²+2mn+n²)=-5mn-n²-10m²-20mn-10n²=-11n²-25mn-10m²2)4x-4√x√y+y+4√(xy)=4x-y