求①x³+9+3x²+3x.的因式分解.

①x³+9+3x²+3x
=(x³+3x²+3x+1)+8
=(x+1)³+8
=(x+1+2)[(x+1)²+4-2(x+1)]
=(x+3)(x²+3)
②2x²+4xy+2y²-8z²
=2[(x²+2xy+y²)-4z²]
=2[(x+y)²-4z²]
=2(x+y+2z)(x+y-2z)

1.
=(x^3+3x^2)+3(x+3)
=(x+3)(x^2+3)
2.
=2[(x+y)^2-4z^2]=2(x+y+2x)(x+y-2z)