1) m³-n³+2n-2m=(m-n)(m²+mn+n²)-2(m-n)=(m-n)(m²+mn+n²-2)
2) 3a³-3b³+5a²-5b²=3(a³-b³)+5(a²-b²)=3(a-b)(a²+ab+b²)+5(a-b)(a+b)=
=(a-b)(3a²+3ab+3b²+5a+5b)
3) x⁶+y⁶+x²+y²=(x²)³+(y²)³+x²+y²=(x²+y²)(x⁴+x²y²+y⁴)+x²+y²=
=(x²+y²)(x⁴+x²y²+y⁴+1)
4) a³-b³+a²-b²=(a-b)(a²+ab+b²)+(a-b)(a+b)=(a-b)(a²+ab+b²+a+b)
5) x⁴+xy³-x³y-y⁴=x⁴-y⁴+xy³-x³y=(x²-y²)(x²+y²)-xy(x²-y²)=
=(x²-y²)(x²+y²-xy)
6) a⁴-a³b+ab³-b⁴=a⁴-b⁴-a³b+ab³=(a²-b²)(a²+b²)-ab(a²-b²)=
=(a²-b²)(a²+b²-ab)