1. a(a+b)-b(a-b)+2(b-a)=a²+ab-ab+b²+2b-2a=a²+b²+2b-2a
2. 2x²-x(2x-5y)-y(2x-y)=2x²-2x²+10xy-2xy+y²=8xy+y²
3. 2xy(2x²-5xy)-3xy(7xy-y²)=4x³y-10x²y²-21x²y²+3xy³=4x³y-31x²y²+3xy³
4. 6m²-5m(2n-m)-4m(3m+2,5n)=6m²-10mn+5m²-12m²-10mn=-2m²-20mn
Объяснение:
