- a^4 - b^4 - c^4 + 2a^2b^2 + 2b^2c^2 + 2 c^2a^2
=2a^2b^2 + 2b^2c^2 + 2 c^2a^2- a^4 - b^4 - c^4
= -(a^4 + b^4 + c^4-2a^2b^2 + 2b^2c^2 - 2 c^2a^2)+4b^2c^2
=(2bc)^2-(a^2-b^2-c^2)^2
=(2bc-a^2+b^2+c^2)(2bc+a^2-b^2-c^2)
Thank You Safal Das Biswas S.A.V.M (Chinsurah)Class X