1.
(4z²-1)(z²+5)=4z4+20z²-z²-5=4z4+19z²-5
(5ab²+4b³)(3ab³-4a²)=15ab5-20a³b²+12ab6-16a²b³
(8a²-3ab)(3a²-ab)=24a4-8a³b-9a³b+3a²b²=24a4-17a³b+3a²b²
(7x³y²-xy)(-2x²y²+5xy)=-14x5y4+35x4y³+2x³y³-5x²y²
(x²+2y-5x)(2x²-3y)=2x4-3x²y+4x²y-6y²-10x³+15xy=2x4+x²y-6y²-10x³+15xy
(a²-5ab+3b²)(a²-2ab)=a4-2a³b-5a³b+10a²b²+3a²b²-6ab³=a4-7a³b+13a²b²-6ab³
2.
(a³+2a²b-5ab²-3b³)(5a-4b)=5a4+10a³b-25a²b²-15ab³-4a³b-8a²b²+20ab³+12b4=
=5a4+6a³b-33a²b²+5ab³+12b4
(x³+3x²y-3xy²+4y³)(2x+3y)=2x4+6x³y-6x²y²+8xy³+3x³y+9x²y²-9xy³+4y4=
=2x4+9x³y+3x²y²-xy³+4y4
(a4+5a³+4a²-3a+1)(a²+2a)=a6+5a5+4a4-3a³+a²+2a5+10a4+8a³-6a²+2a=
=a6+7a5+14a4+5a³-5a²+2a
(2x4-3x³+2x²-5x+1)(2x²-x)= 4x6-6x5+4x4-10x³+2x²-2x5+3x4-2x³+5x²-x=
=4x6-8x5+7x4-12x³+7x²-x
