Ответ:

В решении.

Объяснение:

11.

1)(а-5)²+(а+7)(5-а)+8а=

=а²-10а+25+5а-а²+35-7а+8а=

=60-4а=

=4(15-а);

2)-73+(6+а)²+(9-а)(а+4)=

= -73+36+12а+а²+9а+36-а²-4а=

=17а-1;

3)(3а-4)(9а+8)-(2-27а)(16-а)=

=27а²+24а-36а-32-(32-2а-432а+27а²)=

=27а²+24а-36а-32-32+2а+432а-27а²=

=422а-64=2(211а-32).

12.

1)(а²-5)(3+2а)-2а(а²+4)=

=3а²+2а³-15-10а-2а³-8а=

=3а²-18а-15=3(а²-6а-5);

2)(2-3а)³-4(2-9а)+26а³=

=2³-3*2²*3а+3*2*(3а)²-(3а)³-8+36а+26а³=

=8-36а+54а²-27а³-8+36а+26а³=

=54а²-а³=а²(54-а);

3)(4+а)³-(а-4)³-36(2а²+3)=

=4³+3*4²*а+3*4*а²+а³-(а³-3*а²*4+3*а*4²-4³)-72а²-108=

=64+48а+12а²+а³-а³+12а²-48а+64-72а²-108=

=20-48а²=4(5-12а²).