Question

помогите номер 1 и номер 3

Answer 1

$1.1)27x^3-y^3=(3x-y)(9x^2+3xy+y^2) \\ 2)25a^3-ab^2=a(25a^2-b^2)=a(5a-b)(5a+b) \\ 3)-3x^2-12x-12=-3(x^2+4x+4)=-3(x+2)^2 \\ 4)3ab-15a+12b-60=3(ab-5a+4b-20)=3(a(b-5)+4(b-5)) \\ =3(b-5)(a+4) \\ 5)a^4-625=(a^2-25)(a^2+25)=(a-5)(a+5)(a^2+25) \\ \\ \\ 3.1)7m-n+49m^2-n^2=7m-n+(7m-n)(7m+n)=(7m-n)+ \\ +(1+7m+n) \\ 2)4x^2-4xy+y^2-16=(2x-y)^2-16=(2x-y-4)(2x-y+4) \\ 3)xy^4-2y^4-xy+2y=y(xy^3-2y^3-x+2)=y(y^3(x-2)-(x-2)) \\ =y(x-2)(y^3-1)=y(x-2)(y-1)(y^2+y+1) \\ 4)9-x^2-2xy-y^2=9-(x^2+2xy+y^2)=9-(x+y)^2=(3-(x+ \\ +y))(3+(x+y))=(3-x-y)(3+x+y)$