Объяснение:
1)(2а-5)(1-2а)=2а-4а²-5+10а=12а-4а²-5
2)(3c-2d)(d-c)=3cd-3c²-2d²+2cd=5cd-3c²-2d²
3)(a+в)(3а-в+2)=3а²-ав+2а+3ав-в²+2в=3а²+2а+2ав-в²+2в
4)0,6х³+0,4х²+3=
=0,6*(-2)³+0,4*(-2)²+3=
=0,6*(-8)+0,4*4+3=
= -4,8+1,6+3= -0,2
1)a(n+k)=an+ak
2)2(3a²-4a+8)=
=6a²-8a+16
3)-5(3x³+7x²-x)=
= -15x³-35x²+5x