因式分解3道，谢谢了，加分！

(1)a^3 b^2 - a^2 - b^2 +1
=(a^3 b^2-b^2)-(a^2-1)
=b^2(a^3-1)-(a^2-1)
=b^2(a-1)(a^2+a+1)-(a+1)(a-1)
=(a-1)[b^2(a^2+a+1)-(a+1)]
(2)(m^2-1)(n^2-1)+4mn
=m^2n^2-m^2-n^2+1+4mn
=(m^2n^2+2mn+1)-(m^2-2mn+n^2)
=(m+1)^2-(m-n)^2
=(m+1+m-n)(m+1-m+n)
=(2m-n+1)(n+1)
(3)9a^2-4b^2+4bc-c^2
=9a^2-(4b^2-4bc+c^2)
=(3a)^2-(2b-c)^2
=(3a+2b-c)(3a-2b+c)
解题完毕!

计算中，请稍候……

1:(a-1)(b^2-1)(a^2+a+1)

2:(m*n+m-n+1)*(mn-m+n+1)

3:(3a-2b+c)(3a+2b-c)

---------------------------------------
(1)a^3 b^2 - a^2 - b^2 +1
=(a^3 b^2-b^2)-(a^2-1)
=b^2(a^3-1)-(a^2-1)
=b^2(a-1)(a^2+a+1)-(a+1)(a-1)
=(a-1)[b^2(a^2+a+1)-(a+1)] =====》 = (a-1)(b^2-1)(a^2+a+1) (楼上的答案是错误的)
(2)(m^2-1)(n^2-1)+4mn
=m^2n^2-m^2-n^2+1+4mn
=(m^2n^2+2mn+1)-(m^2-2mn+n^2)
=(m+1)^2-(m-n)^2
=(m+1+m-n)(m+1-m+n)
=(2m-n+1)(n+1)
(3)9a^2-4b^2+