【急!】几道初中的因式分解1.a^4-8a^2b^2+16b^42.-4a^3+16a^2b-16ab^23.4(2x-

a^4-8a^2b^2+16b^4=(a^2)^2-8a^2b^2+(4b^2)^2={a^2-(4b^2)^2}^2={(a+2b)(a-2b)}^2
-4a^3+16a^2b-16ab^2=-4a(a^2+4ab-4b^2)=-4a(a-2b)^2
4(2x-1)^2-9x^2={2(2x-1)}^2-{3x}^2={4x-2}^2-{3x}^2=(4x-2-3x)(4x-2+3x)==(x-2)(7x-2)
4(x^2+1)^2-16x^2=4{(x^2+1)^2-4x^2}=4{(x^2+1)+2x}{(x^2+1)-2x}=4(x+1)^2(x-1)^2
(a^2+4)^2-16a^2= (a^2+4)^2-(4a)^2= {(a^2+4)-4a}{(a^2+4)+4a}=(a-2))^2}(a+2))^2