Сократите 1) (x+2)(x-9)-3x(3-2x) 2) (a+5)(a-2)+(a+4)(a-5) 3) (y-8)(2y+1)-(3y+1)(y-6).

Question

Сократите
1) (x+2)(x-9)-3x(3-2x) 2) (a+5)(a-2)+(a+4)(a-5) 3) (y-8)(2y+1)-(3y+1)(y-6).

Answer 1

1)=х^2-9х+2х-18-9х+6х^2=
=7х^2-16х-18
2)=а^2-2а+5а-10+а^2-5а+4а-20=
=2а^2+2а-30
3)=2у^2+у-16у-8-3у^2+18у-у+6=
=2у-у^2-2