题目内容
(1)2a-2b=2(a-b);
(2)y2-=;
(3)ax+ay=a(x+y);
(4)11a5b7c=11·a5·b7·c;
(5)(x+3)(x-3)=x2-9;
(6)x2-y2+4=(x+y)(x-y)+4;
(7)m(m-n)+n(n-m)=(m-n)2;
(8)y+1=y(1+);
(9)4a2+10ab=2a(2a+5b);
(10).
(1)为了分组后直接提取公因式,下面哪种分组是对的?哪种分组是错的?
①3x2-2y+6xy-x=(3x2-2y)+(6xy-x);
②3x2-2y+6xy-x=(3x2+6xy)+(-2y-x);
③3x2-2y+6xy-x=(3x2-x)+(-2y+6xy).
(2)为了分组后直接用公式分解因式,下列分组哪种是对的?哪种是错的?
①x2-y2-2y-1=(x2-y2)-(2y+1);
②x2-y2-2y-1=(x2-1)-(y2+2y);
③x2-y2-2y-1=x2-(y2+2y+1).
(3)把x3+4x2+4x+3分解因式
原式=x3+x2+x+3x2+3x+3=x(x2+x+1)+3(x2+x+1)=(x2+x+1)(x+3).
(4)把x2+x-4y2-2y分解因式,按下列分组方法进行分解
①原式=(x2+x)-(4y2+2y);
②原式=(x2-4y2)+(x-2y);
③原式=(x2+x-2y)-4y2.
判断下列因式分解是否正确,并把错误的改正过来.
(1)16x6-y2=(4x3+y)(4x3-y);
(2)a16-b9=(a4+b3)(a4-b3).