Question 479310
given that {{{x^4+4y^4=(x^4+4x^2y^2+4y^4)-4x^2y^2}}}, I need to complete the factorization of {{{x^4+4y^4}}} by using the difference of squares 

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= {{{(x^2 + 2y^2 + 2xy)*(x^2 + 2y^2 - 2xy)}}}
or  {{{(x^2 + 2xy + 2y^2)*(x^2 - 2xy + 2y^2)}}}