Factorize:
(i) `(a^4-8a^2b^2+16 b^4)-256`
(ii) `a^4-6a^2b^2+9b^4-81`

Explanation

Let's factorize the given expressions step by step.

### (i) Factorize: \( a^4 - 8a^2b^2 + 16b^4 - 256 \)

**Step 1:** Rewrite the expression in a more manageable form.
\[ a^4 - 8a^2b^2 + 16b^4 - 256 = (a^4 - 8a^2b^2 + 16b^4) - 256 \]
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