Ответ:

а)2(b+1)²-4b

(b+1)²=b²+2b+1

2(b²+2b+1)=2b²+4b+2

2b²+4b+2-4b=2b²+2=2(b²+1)

b)4a(a-2)-(a-4)²

(a-4)²=a²-8a+16

4a(a-2)=4a²-8a

4a²-8a-a²+8a-16=3a²-16

в)

(x-3)²=x²-6x+9

(x-1)(x+4)=x²+3x-4

(x-2)(x+2)=x²-4

x²-6x+9-x²-3x+4+x²-4=x²-9x+9

г)

(3-c)(3+c)=9-c²

(9-c²)(9+c²)=81-c⁴

(c-2)(c²+2c+4)=c³-8

81-c⁴-c³+8=89-c⁴-c³