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A卷为第Ⅰ卷和第Ⅱ卷,满分100分,B卷满分50分 A卷(共100分) 第I卷(选择题,共60分)一、选择题:(每小题4分,共60分)1.|-1/5|的倒数是( ).(A)-5(B)5(C)1/5(D)-1/52.下列运算中,不正确的是( ).(A)3xy-(x2-2xy)=5xy-x2(B)2ab2·4ab2=9a2b4(C)5x(2x2-y)=10x3-5xy(D)(X+3)(x2-3x+9)=x2+93.在平杯四边形、矩形、菱形、等腰三角形中,既是中心对称图
A volume is the first volume and the second volume, out of 100 points, B volume out of 50 points A volume (100 points in total) Volume I (multiple choice, a total of 60 points) a multiple-choice questions: (each question 4 points, A total of 60 points) The inverse of 1.|-1/5| is ().(A)-5(B)5(C)1/5(D)-1/52. In the following operations, it is incorrect ( (A) 3xy-(x2-2xy)=5xy-x2(B)2ab2·4ab2=9a2b4(C)5x(2x2-y)=10x3-5xy(D)(X+3)(x2-3x+) 9) = x2 + 93. In the flat cup quadrilateral, rectangular, diamond, isosceles triangle, is the center symmetry