问题 解答题
计算:
①(-
1
3
a3b22•(-2ab23÷(
1
9
a4b43    ②(x-2y)(x+2y)-(x+2y)2
答案

①原式=

1
9
a6b4•(-8a3b6)÷(
1
729
a12b12)=-
8
9
a9b10×
729
a12b12
=
-648
a3b2

②原式=(x+2y)[(x-2y)-(x+2y)]=(x+2y)[x-2y-x-2y]=(x+2y)[-4y]=-4xy-8y2

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