因式分解練習

1(a) 3b-ab
b(3-a)



b) 9-a^2
(3-a)(3+a)



c)9-a^2+3b-ab
(9-a^2)+b(3-a)
(3-a)(3+a)+b(3-a)
(3-a)(a+b-3)

2010-01-30 15:34:26 補充：
c)9-a^2+3b-ab
(9-a^2)+b(3-a)
(3-a)(3+a)+b(3-a)
(3-a)(a+b+3)

2010-01-30 17:32:40 補充：
2(a) 4x^2-4xy+y^2
(b) 4x^2-4xy+y^2-2x+y

(a)4x^2-4xy+y^2
(2x-y)^2

(b)4x^2-4xy+y^2-2x+y
(2x-y)(2x-y)-(2x-y)
(2x-y)(2x-y-1)

2010-01-30 17:34:57 補充：
3(a) a^2-ab+2a-2b
(b) 169y^2-25

a^2-ab+2a-2b
a(a-b)+2(a-b)
(a-b)(a+2)

169y^2-25
(13y-5)(13y+5)

2010-01-30 17:37:04 補充：
4(a) x^2-(y-z)^2
(b) ab-ad-bc+cd


x^2-(y-z)^2
(x-y+z)(x+y-z)


(b) ab-ad-bc+cd
a(b-d)-c(b-d)
(a-c)(b-d)

2010-01-30 17:38:31 補充：
5(a) x^2-9
(b) ac+bc-ad-bd


5(a) x^2-9
(x+3)(x-3)

ac+bc-ad-bd
c(a+b)-d(a+b)
(c-d)(a+b)

2010-01-30 17:41:56 補充：
超凡學生的第五B條打錯!!

1(a) 3b-ab
=b(3-a)

(b) 9-a2
=32-a2
=(3-a)(3+a)

(c) 9-a2+3b-ab
=(3-a)(3+a)+ b(3-a)
=(3-a)(3+a+b)

2(a) 4x2-4xy+y2
=(2x)2-2(2x)(y)+y2
=(2x-y)2

(b) 4x2-4xy+y2-2x+y
=(2x-y) 2-(2x-y)
=(2x-y)(2x-y-1)

3(a) a2-ab+2a-2b
=a(a-b)+2(a-b)
=(a-b)(a+2)

(b) 169y2-25
=(13y)2-52
=(13y-5)(13y+5)

4(a) x2-(y-z)2
=[x-(y-z)] [x+(y-z)]
=(x-y+z)(x+y-z)

(b) ab-ad-bc+cd
=a(b-d)-c(b-d)
=(b-d)(a-c)

5(a) x2-9
=x2-32
=(x-3)(x+3)

(b) ac+bc-ad-bd
=c(a+b)-d(a+b)
=(a+b)(a-d)