您好!
1.
x^4-4x^3+4x^2-9
=x^2[x^2-4x+4]-9
=x^2[x-2]^2-9
=[x(x-2)+3][x(x-2)-3]
=[x^2-2x+3][x^2-2x-3]
=[x^2-2x+3][x-3][x+1]
2.
y^5-11y^3+y
=y（y^4-2y^2+1-9y^2）
=y[（y^2-1）^2-9y^2]
=y（y^2+3y-1）
=y^2-3y-1