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计算:(1)(ab2)2•(-a3b)3÷(-5ab)(2)x2-(x+2)(x-2)-(x+1x

来源:学生作业帮 编辑:作业帮 分类:数学作业 时间:2024/05/13 16:54:23
计算:
(1)(ab22•(-a3b)3÷(-5ab)
(2)x2-(x+2)(x-2)-(x+
1
x
(1)原式=a2b4•(-a9b3)÷(-5ab)
=-a11b7÷(-5ab)
=
1
5a10b6
(2)x2-(x+2)(x-2)-(x+
1
x)2
=x2-x2+4-x2-2-
1
x2
=2-x2-
1
x2;
(3)[(x+y)2-(x-y)2]÷(2xy)
=[x2+2xy+y2-x2+2xy-y2]÷(2xy)
=4xy÷(2xy)
=2.