1) -(a-3)(2-3a)=(3-a)(3a-2)
-(а-3)(2-3а)=-(2а-3а²-6+9а)=-(-3а²+11а-6)=3а²-11а+6
(3-а)(3а-2)=9а-6-3а²+2а=-3а²+11а-6
3а²-11а+6≠-3а²+11а-6
-(a-3)(2-3a)=(3-a)(3a-2) неверно
2) (5-а)(а+5)=25-а^2
(5-а)(а+5)=(5-а)(5+а)=25-а²
25-а²=25-а²
(5-а)(а+5)=25-а^2 верно
3) (а-6)^2 = a^2-6a+36
(а-6)²=а²-12а+36
а²-12а+36≠а²-6а+36
(а-6)^2 = a^2-6a+36 неверно
4) -(7+a)(2a-3)=21-11a-2a^2
-(7+а)(2а-3)=-(14а-21+2а²-3а)=-(2а²+11а-21)=-2а²-11а+21
-2а²-11а+21=-2а²-11а+21
-(7+a)(2a-3)=21-11a-2a^2 верно
Ответ: 2,4