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试题原文 |
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(1)原式=(2x-3y)2-(9x2-y2), =(4x2+9y2-12xy)-9x2+y2, =10y2-12xy-5x2; (2)原式=(x+y)(x2+y2)(x-y)(x4+y4), =(x2-y2)( x2+y2)(x4+y4), =(x4-y4)(x4+y4), =x8-y8; (3)原式=[a-(2b-3)][a+(2b-3)], =a2-(2b-3)2, =a2-4b2-9+12b; (4)原式=[(x-y)2+(x+y)2](x2-y2), =(x2-2xy+y2+x2+y2+2xy)(x2-y2), =2(x2+y2)(x2-y2), =2(x4-y4), =2x4-2y4; (5)原式=(m-n-3)(m-n-3), =m2-mn-3m-mn+n2+3n-3m+3n+9, =n2+m2-2mn-6m+6n+9. |
经过对同学们试题原文答题和答案批改分析后,可以看出该题目“利用乘法公式计算:(1)(2x-3y)2-(y+3x)(3x-y);(2)(x+y)(x2+y2)(x..”的主要目的是检查您对于考点“初中平方差公式”相关知识的理解。有关该知识点的概要说明可查看:“初中平方差公式”。