Ответ:

1)-2(3х-2у)-5(2у-3х)=-6х+4у-10у+15х=9х-6у=3(3х-2у)

2)(х^2-1)×3х-(х^2-2)×2х=3х^3-3х-2х^3+4х=х^3+х=х×(х^2+1)

3)2(2а^2-4а+8)=4а^2-8а+16=4(а^2-4а+4)

4)(3а-5b+bc)(-3)=-9a+18b-3bc

5)(9-a)(8+a-b)=72-9b-8a-a^2+ab

6)

(4a-5c)×(-a+3c)=-4a^2+12ac+5ac-15c^2=-4a^2+-7ac-15c^2

7)(3-c)(8+y)+(c-4)(y+6)=24+3y-8c-cy+cy+6c-4y-24=

y-2c

8)(5-x)(x+5)+(x-3)(x-7)=5x+25-x^2-5x+x^2-7x-3x+21=46-10x=2(23-5x)

9=(x-5)^2-(x-3)(x-7)=(x-5)(x-5)-(x-3)(x-7)=x^2-5x-5x+25-x^2+7x+3x-21=4

10)(2x-3)^2-2x(4+2x)=(2x-3)(2x-3)-8x-4x^2=4x^2-12x+9-8x-4x^2=9-20x