1) 4c(c-2) - (c-4)²=4c²-8c-c²+8c-16=3c²-16
2) 3a(a+2) - (a+3)²=3a²+6a-a²-6a-9=2a²-9
3) 3(y-1)²+6y=3(y²-2y+1)+6y=3y²-6y+3+6y=3y²+3
4) 8c+4(1-c)²=8c+4(1-2c+c²)=8c+4-8c+4c²=4c²+4
5) 4ab+2(a-b)²=4ab+2(a²-2ab+b²)=4ab+2a²-4ab+2b²=2a²+2b²
6) 3(x+y)²-6xy=3(x²+2xy+y²)-6xy=3x²+6xy+3y²-6xy=3x²+3y²
7) 3a(a-2)-(a-3)²=3a²-6a-a²+6a-9=2a²-9
8) (a-4)²-2a(3a-4)=a²-8a+16-6a²+8a=16-5a²
9) (x-y)²-x(x-2y)=x²-2xy+y²-x²+2xy=y²
10) a(a+2b)-(a+b)²=a²+2ab-a²-2ab-b²=-b²
11) (a-3)(a-7)-2a(3a-5)=a²-7a-3a+21-6a²+10a=21-5a²
12) (x-2)(x+4)-2x(1+x)=x²+4x-2x-8-2x-2x²=-x²-8
13) 2c(3c+4)-3c(2c+1)=6c²+8c-6c²-3c=5c
14) 3a(2a-1)-2a(4+3a)=6a²-3a-8a-6a²=-11a
15) (b+c)(b-c)-b(b-2c)=b²-c²-b²+2bc=2bc-c²
16) (a-c)(a+c)-c(3a-c)=a²-c²-3ac+c²=a²-3ac
17) a(a+5b)-(a+b)(a-b)=a²+5ab-a²+b²=b²+5ab
18) b(3a-b)-(a-b)(a+b)=3ab-b²-a²+b²=3ab-a²
19) (y+10)(y-2)-4y(2-3y)=y²-2y+10y-20-8y+12y²=13y²-20
20) (a-4)(a+9)-5a(1-2a)=a²+9a-4a-36-5a+10a²=11a²-36
21) (2b-3)(3b+2)-3b(2b+3)=6b²+4b-9b-6-6b²-9=-5b-15
22) (3a-1)(2a-3)-2a(3a+5)=6a²-9a-2a+3-6a²-10a=-21a+3
23) (m+3)²-(m-2)(m+2)=m²+6m+9-m²-4=6m+5
24) (a-1)²-(a+1)(a-2)=a²-2a+1-a²+2a-a+2=3-a
25) (c+2)(c-3)-(c-1)²=c²-3c+2c-6-c²+2c-1=c-7
26) (y-4)(y+4)-(y-3)²=y²-16-y²+6y-9=6y-25
27) (a-2)(a+4)-(a+1)²=a²+4a-2a-8-a²-2a+1=-7
28) (b-4)(b+2)-(b-1)²=b²+2b-4b-8-b²+2b-1=-4b-9