(word完整版)七年级数学下册第一章知识点总结

(3)(x2y)6·(x2y)3 (4)[(x?y)2n]4?(?x?y)2n?1 (n是正整数).

9.若(3x+2y-10)0无意义,且2x+y=5,求x、y的值.(6分)

整式的乘法及平方差公式与完全平方公式的运算

y?2y3)= 1.3x(x-2y)= ; ?4a(a-2b)= ; ?4x2(12x2y)(1(x2-2x?1)(-3x)= ; (-23xy?2x2xy)= (2x+5)(x-3)= ;(x-3y)( x-5y)= ；（2x-3y)( 3x-5y)=

3

2. 2x2y·(1－3xy+y)的计算结果是( ) 2A.2x2y4－6x3y2+x2y B.－x2y+2x2y4 C.2x2y4+x2y－6x3y2 D.－6x3y2+2x2y4 3. 计算(2x-1)(5x+2)的结果是( )

A.10x2-2 B.10x2-5x-2 C.10x2+4x-2 D.10x2-x-2 4.计算

5

①(a-3) ( a+3) ②2a(?2ab?ab2); ③y2(y?y2); ④3x2(－y－xy2＋

1312x2)；

⑤(?4xy)?(xy?3x2y); ⑥(?xy)(x2y?xy2?y); 1236

⑦(3x－2y)(2x－3y);

⑨(3x－2y)(3x+2y)

2325⑧(3x+2)(-x-2); ⑩( a+3)( a+3) 6