1.
1)(2у+1)(5у-6)=10у^2-12у+5у-6=10у^2-7х-6
2)(3а-b)(2a-7b)=6a^2-21a^2-2ab+7b^2=6a^2-23ab+7b^2
3)(a-4b)(a^2+3ab-6b^2)=a^3+3a^2b-6ab^2-4a^2b-12ab^2+24b^3=a^3-a^2b-18ab^2+24b^3
3)a(4a-5)(2a+3)=(4a^2-5a)(2a+3)=8a^3+12a^×-10a^2-15a=8a^3+2a^2-15a
1.(3m-4n)(3m+5n)-(4,5m-n)(2m+4n)=9m^2+15mn-12mn-20n^2-9m^2-16mn+4n^2=-113mn-16n^2
2.(x+6)(x-1)-(x+3)(x-4)=5x
x^2-x+6x-6-x^2+x+12=5x
6x+6=5x
x=-6
4.(y+1)(y-3)=y^2-3y+y-3=y^2-2y-3