We can use the difference of squares formula for both $x^4 - y^4$ and $x^2 - y^2$. The difference of squares formula states that $a^2 - b^2 = (a + b)(a - b)$.
Applying this formula to $x^4 - y^4$, we get:
$$
x^4 - y^4 = (x^2 + y^2)(x^2 - y^2)
$$
Applying this
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