factorise-x^4-y^4+x^2-y^2

Answer 1

x^4-y^4+x^2-y^2
(x^2-y^2)(x^2+y^2) + (x^2-y^2)
(x^2-y^2)(x^2+y^2+1)
(x-y)(x+y)(x^2+y^2+1)