计算:(1)a(a+2)2(2)(2x+y)(2x-y)+(-x)(4x-y)(3)4(x+y)2-9(x-y)2(4)(-3x2y3)2-(-2x3y2)3÷
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计算: (1)a(a+2)2 (2)(2x+y)(2x-y)+(-x)(4x-y) (3)4(x+y)2-9(x-y)2 (4)(-3x2y3)2-(-2x3y2)3÷(-2x5y5)2. |
答案
(1)a(a+2)2 =a(a2+4a+4) =a3+4a2+4a;
(2)(2x+y)(2x-y)+(-x)(4x-y) =4x2-y2-4x2+xy =-y2+xy;
(3)4(x+y)2-9(x-y)2 =4(x2+2xy+y2)-9(x2-2xy+y2) =4x2+8xy+4y2-9x2+18xy-9y2 =-5x2+26xy-5y2;
(4)(-3x2y3)2•(-2x3y2)3÷(-2x5y5)2 =(9x4y6)•(-8x9y6)÷(4x10y10) =(-72x13y12)÷(4x10y10) =-18x3y2. |
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