1) a(3a^2+a)= 3а^3+a^2
2) b(2b^3-7)= 2b^4-7b
3)-p^2(3g-2p)=-3p^2g+2p^3
4) 5(a^2-2ab+b^2)=5a^2-10ab+5b^2
5) 2m(m^2-3m+3)= 2m^3-6m^2+6m
6) -3(x^2+xy+y^2)= -3x^2-3xy-3y^2
7) a(a+b)-b(a-b)=a^2+ab-ab+b^2=a^2-b^2
8) 2x(x-y)-y(y-2x)= 2x^2-2xy-y^2+2xy=2x^2-y^2
9) a(a^2-1)+a^2(a-1)=a^3-a+a^3-a=2a^3-2a