习题9.5第1题答案
解:(1)ap-aq+am=a(p-q+m).
(2)4x2-8xy+2x=2x(2x-4y+1).
(3)12xyz-9x2y=3xy(4z-3x).
(5)6a2b-9ab2+15ab=3ab(2a-3b+5).
习题9.5第2题答案
解:(1)4ab(2x-y)+b(2x-y)=b(2x-y)(4a+1);
(2)6a(1-b) 2-2(b-1) 2=2(b-1) 2•(3a-1).
习题9.5第3题答案
解:(1)1-16a2=(1+4a)(1-4a);
(2)m2-9n2=(m+3n)(m-3n);
(3)4x2-81y2=(2x) 2-(9y2)=(2x+9y)(2x-9y);
(4)9a2x2-b2y2=(3ax+by)(3ax-by).
习题9.5第4题答案
解:(1)(x+5) 2-4=(x+5) 2-22=(x+5+2)(x+5-2)=(x+7)(x+3);
(2)(a+b) 2-a2=(a+b+a)(a+b-a)=b(2a+b);
(3)(a2+b2)2-a2b2=(a2b2+ab)(a2b2-ab);
(4)49(a-b)2-16(a+b)2
=[7(a-b)] 2-[4(a+b)] 2
=[7(a-b)+4(a+b)][7(a-b)-4(a-b)]
=(7a-7b+4a+4b)(7a-7b-4a-4b)
=(11a-3b)(3a-11b).
习题9.5第5题答案
解:(1)a2b2-2ab+1=(ab-1)2;
(2)9-12a+4a2=(2a-3)2;
(3)4x2+4x+1=(2x+1)2;
(4)x2-6xy+9y2=(x-3y)2.
习题9.5第6题答案
解:(1)(a+b)2+6(a+b)+9=(a+b+3)2;
(2)16-24(x-y)+9(x-y)2=[3(x-y)-4]2=(3x-3y-4)2;
(3)a2-2a(b+c)+(b+c)2=[a-(b+c)]2=(a-b-c)2;
(4)4x2-4x(y-1)+(y-1)2=[2x-(y-1)]2=(2x-y+1) 2.
习题9.5第7题答案
解:(1)-a+2a2-a3=-a(1-2a-22)=-a(a-1)2;
(2)3ax2-3ay2=3a(x2-y2)=2a(x+y)(x-y);
(3)16a2b-13a2-4ab2=-4a(4a2-4ab+b2)=-4a(2a-b) 2;
(4)x2(y2-1)+(1-y2)=(y2-1)(x2-1)=(y+1)(y-1)(x+1)(x-1).
习题9.5第8题答案