267.
1) ac²-ad+c³-cd-bc²+bd=(ac²-ad)+(c³-cd)-(bc²-bd)=
=a(c²-d)+c(c²-d)-b(c²-d)=(c²-d)(a+c-b)
3) am²+cm²-an+an²-cn+cn²=(am²+cm²)-(an+cn)+(an²+cn²)=
=m²(a+c)-n(a+c)+n²(a+c)=(a+c)(m²-n+n²)=(a+c)(m²+n²-n)
4) xy²-ny²-mx+mn+m²x-m²n=(xy²-ny²)-(mx-mn)+(m²x-m²n)=
=y²(x-n)-m(x-n)+m²(x-n)=(x-n)(y²-m+m²)=(x-n)(m²+y²-m)
5) a²b+a+ab²+b+2ab+2=(a²b+ab²+2ab)+(a+b+2)=
=ab(a+b+2)+(a+b+2)=(a+b+2)(ab+1)