(3х-у)-4у²=9х²-6ху+у²-4у²=9х²-6ху-3у²=3(3х²-2ху-у²)=3(х-у)(3х+у)
(3x-y)^2-4y^2 =
= 9x^2-6xy+y^2-4y^2=
= 3×(3x^2-2xy-y^2)=
=3×(x-y)×(3x+y).
(3х-у)-4у²=9х²-6ху+у²-4у²=9х²-6ху-3у²=3(3х²-2ху-у²)=3(х-у)(3х+у)
(3x-y)^2-4y^2 =
= 9x^2-6xy+y^2-4y^2=
= 3×(3x^2-2xy-y^2)=
=3×(x-y)×(3x+y).