Answers

2015-07-29T22:36:20+08:00
(x+1)² or (x+1)(x+1) = x²+2x+1
(x-1)² or (x-1)(x-1) = x²-2x+1

(x²+2x+1)(x²-2x+1)
= x⁴-2x²+1, my answer
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