a) (2x + 1)2 +(2x + 3)2 – 2(2x + 1)(2x + 3) c) (x + 2y)(x2 – 2xy + 4y2) – (x – y)(x2 + xy + y2)d) x2(x + y) + y2(x + y) + 2x2y + 2xy2
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