(a-b-2c)² 用乘法公式计算 怎么算?
人气:304 ℃ 时间:2020-03-16 07:31:21
解答
(a-b-2c)²
=[(a-b)-2c]²
=(a-b)²-4c(a-b)+(2c)²
=a²-2ab+b²-4ac+4bc+4c²
=a²+b²+4c²-2ab-4ac+4bc
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