⑴﹣¼a²﹢3a﹣9⑵3x³-12x²y﹢12xy²
问题描述:
⑴﹣¼a²﹢3a﹣9⑵3x³-12x²y﹢12xy²
答
(1)-(1/2a-3)²
(2)3x(x²-4xy﹢4y² )
=3x(x-2y)²