Сразу решение без условия:
1. =5(4а²-9b²)=5(2a-3b)(2a+3b)
2. = 2ab(64a²-b²)=2ab(8a-b)(8a+b)
3. =(x²-y²)(x²+y²)=(x-y)(x+y)(x²+y²)
4. = (x⁴-y⁴)(x⁴+y⁴)=(x²-y²)(x²+y²)(x⁴+y⁴)=(x-y)(x+y)(x²+y²)(x⁴+y⁴)
5. =(a²-1)(a²+1)=(a-1)(a+1)(a²+1)
6. =(1-9y²)(1+9y²)=(1-3y)(1+3y)(1+9y²)
7. = (9a²x²-225a²)+(100b²-4b²x²)=9a²(x²-25)+4b²(25-x²)=9a²(x²-25)-4b²(x²-25)=
=(x²-25)(9a²-4b²)=(x-5)(x+5)(3a-2b)(3a+2b)
8. = (16a²c²-144b²c²)-(25a²-225b²)=16c²(a²-9b²)-25(a²-9b²)=(a²-9b²)(16c²-25)=
=(a-3b)(a+3b)(4c-5)(4c+5)
9. = (a²b³-a²b)-(b³-b)=a²b(b²-1)-b(b²-1)=(b²-1)(a²b-b)=b(a²-1)(b²-1)=
=b(a-1)(a+1)(b-1)(b+1)
10. = (a³b²-a³)+(4a-4ab²)=a³(b²-1)+4a(1-b²)=a³(b²-1)-4a(b²-1)=(b²-1)(a³-4a)=
=a(a²-4)(b²-1)=a(a-2)(a+2)(b-1)(b+1)
11. Плохо видно.
12. =(2a³+a²x)-(8ax²+4x³)=a²(2a+x)-4x²(2a+x)=(2a+x)(a²-4x²)=
=(2a+x)(a-2x)(a+2x)
13. =(a²-b²)+(a+b)=(a-b)(a+b)+(a+b)=(a+b)(a-b+1)
14. =(4a²-9x²)+(15x+10a)=(2a-3x)(2a+3x)+5(3x+2a)=(3x+2a)(2a-3x+5)
15. = (9x²-y²)-(6x-2y)=(3x-y)(3x+y)-2(3x-y)=(3x-y)(3x+y-2)
16. = (a²b²-a²)-(ab²+ab)=a²(b²-1)-ab(b+1)=a²(b-1)(b+1)-ab(b+1)=
=(b+1)(a²(b-1)-ab)=(b+1)(a²b-a²-ab)=a(b+1)(ab-a-b)