题目内容
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计算
(1)(-2x2yz3)·(xy2-xz+);
(2)(-a2b3-ab+2bc)·(-a2b).
(-89)×(+9)
(1-2)×(2-3)×(3-4)×(4-5)×…×(19-20).
用简便方法计算÷(-7)
(-)÷(+3)
a3·a4·a+(a2)4+(-2a4)2
(1)7(x-3)-5(2x+1);
计算:
(1)20.05×52+20.05×74-20.05×26
(2)9×102004-102005