内容正文:
练闯考
的
数学七年级下册沪科版
专题(七)
因式分解
a(3a+1)
x2y(3xy-y2+2x2)
5a(x-y)(a-2)
(x+62
3x+4y)3x-4y)
(11a+7b)7a+11b)
解:原式=(x一1)一52=(x一6)2
解:原式=(x2+9y2+6xy)x2+9y2-6xy)=(x+3y)2(x-3y)2
m(a十b)(a-b)
n(m-2)2
解:原式=(x-y)9a2-4b2)=(一y)3a+2b)3a-2b)
解:原式=a(x2+y2)(x2-y)=a(2+y2)+y(x一y)
(m-y)(3+a)
(x-2y)x+2y+2)
解:原式=(x一y)2-9=(一y+3)《一y-3)
解:原式=(x2-6xy+9y2)-(3x-9y)=(K一3y)2-3(x一3y)=(K-3y)x一3y一3)
解:原式=x2-2x+1十2x-10=x2-9=(x十3)K-3)
解:原式=4xy-4x2-y2=-(4x2-4xy+y2)=-(2x-y)2