1)3a(a-4)-2a(a+3)
3a²-12a-2a²-6a=a²-18a
(d+2)(d-3)+(d-3)²=(d-3)(d+2+d-3)=
=(d-3)(2d-1)=2d²-6d-d+3=2d²-7d+3
3(f+3)²-3f²=3f²+18f+27-3f²=18f+27
2)d³-49d=d(d²-49)=d(d+7)(d-7)
4v²-8dv+4d²=4(v-d)²=4(d-v)²
3)(4y-y²)²-y²(y-4)(y+4)+3y(8+6y²)=
=-y²(y-4)(y-4)-y²(y-4)(y+4)+2y(12+9y²)=
=-y²(y-4)(y-4+y+4)+2y(12+9y²)=
=y²(4-y)2y+2y(12+9y²)=
=2y(4y²-y³)+2y(12+9y²)=2y(-y³+13y²+12)=
=-2y⁴+26y³+24y
4)1u⁴—81=u⁴—3⁴=(u²—3²)(u²+3²)=
=(u-3)(u+3)(u²+9)
u²-b²-2b-1=-b(b+2)+(u-1)(u+1)