Ответ:

3)

x³-x²y-xy²+y³=x³+y³-xy(x+y)=(x+y)(x²-xy+y²)-xy(x+y)=

=(x+y)(x²-xy+y²-xy)=(x+y)(x²-2xy+y²)=(x+y)(x-y)(x-y)=

=(x+y)((x-y)²

4)

a^3+a^2b-ab^2-b^3=

=a^2(a+b)-b^2(a+b)=

=(a^2-b^2) (a+b)

5)

m²+2mn+n²-mb-nb=(m²+2mn+n²)-(mb+nb)=(m+n)² -b(m+n)=(m+n)(m+n-b)

6)

xc-yc-x²+2xy-y²=c(x-y)-(x-y)²=(x-y)(c-x+y)

как то так