几道代数因式分解题1.3a(b²+9)²-108ab²2.3a(x²+4)&su

3a(b²+9)²-108ab²
=3a[(b^2+9)^2-36b^2]
=3a(b^+9-6b)(b^2+9+6b)
=3a(b-3)^2(b+3)^2
2.3a(x²+4)²-48ax²
=3a[(x^2+4)^2-16x^2]
=3a(x^2+4+4x)(x^2+4-4x)
=3a(x+2)^2(x-2)^2
3.x^4(a-2b)+x²y²(2b-a)
=x^2(a-2b)(x^2-y^2)
=x^2(a-2b)(x+y)(x-y)