1、 x^3-27y^3
=x^3-(3y)^3
=(x-3y)(x^2+3xy+9y^2)
2.8m^3+27n^3
=(2m)^3+(3n)^3
=(2m+3n)(4m^2-6mn+9n^2)
3.8x^3y-18xy^3
=2xy(4x^2-9y^2)
=2xy(2x+3y)(2x-3y)
4.16m^4n-54mn^4
=2mn(8m^3-27n^3)
=2mn[(2m)^3-(3n)^3]
=2mn(2m-3n)(4m^2+6mn+9n^2)
5.50m^2-32n^2
=2(25m^2-16n^2)
=2(5m+4n)(5m-4n)
6.x^2-4y^2-6x+9
=(x^2-6x+9)-4y^2
=(x-3)^2-(2y)^2
=(x+2y-3)(x-2y-3)