问题 解答题
计算:
(1)(
1
4
)-2-(3-π)0+23

(2)(x+2y)(x-2y)-(x-2y)2
答案

(1)(

1
4
)-2-(3-π)0+23

=16-1+8

=23;

(2)(x+2y)(x-2y)-(x-2y)2

=x2-4y2-x2+4xy-4y2

=4xy-8y2

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