1)27x³-y³=(3x-3)(9x²+9x+y²)
2)25a³-ab²=a(25a²-b²)=a[(5a-b)(5a+b)]
3)-3x²-12x-12=-3(x²+4x+4)=-3(x+2)²=-3(x+2)(x+2)
4)3ab-15a+12b-60=3a((b-5)+12(b-5)=(b-5)(3a+12)=3(b-5)(a+4)
5)a³-625=a³-(5√5)³)=(a-5√5)(a²+5a√5+125)
1)7m+49m²-n-n²=(7m-n)+(49m²-n²)=
=(7m-n)+(7m-n)(7m+n)=(7m-n)(1+7m+n)
2)4x²-4xy+y²-16=(2x-y)²-16=(2x-y-4)(2x-y+4)
3)xy^4-2y^4-xy+2y=y^4(x-2)-y(x-2)=(x-2)(y^4-y)
4)9-x²-2xy-y²=9-(x²+2xy+y²)=9-(x+y)²=[3-(x-y)][3+(x+y)]=
=(3-x-y)(3+x+y)