Prove that (3n+1)2−(3n−1)2(3n + 1)^2 - (3n - 1)^2(3n+1)2−(3n−1)2 is always a multiple of 12, for all positive integer values of nnn.
Hence prove that (3n+1)4−(3n−1)4(3n + 1)^4 - (3n - 1)^4(3n+1)4−(3n−1)4 is always a multiple of 24, for all positive integer values of nnn.
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