求助4m^2n^2-(m^2+n^2-x^2)^2因式分解!

题目

求助4m^2n^2-(m^2+n^2-x^2)^2因式分解!
4m^2n^2-(m^2+n^2-x^2)^2 请问这道题的解答步骤应该是怎样的,希望高手前来指教~

答案

原式=(2mn)^2-(m^2+n^2-x^2)^2
=-(m^2+n^2+2mn-x^2)(m^2+n^2-2mn-x^2)
=-[(m+n)^2-x^2][(m-n)^2-x^2]
=-(m+n+x)(m+n-x)(m-n+x)(m-n-x)