Factorize

1. y^2 + 6y + 9
=y^2+2(y)(3)+3^2
=(y+3)^2

2.x^2 - 4
=x^2-2^2
=(x+2)(x-2)

3.1 - 25x^2
=1^2-(5x)^2
=(1+5x)(1-5x)

4. 49x^2 - 1
=(7x)^2-1^2
=(7x+1)(7x-1)

5.9a^2 - 16
=(3a)^2-4^2
=(3a+4)(3a-4)

6.16 - 4y^2
=4(2^2-y^2)
=4(2+y)(2-y)

7. 36p^2 - 49
=(6p)^2-7^2
=(6p+7)(6p-7)

8. x^2 - 16y^2
=x^2-(4y)^2
=(x+4y)(x-4y)

9. 25x^2 - 9y^2
=(5x)^2-(3y)^2
=(5x+3y)(5x-3y)

10. 16a^2 - 25b^2
=(4a)^2-(5b)^2
=(4a+5b)(4a-5b)

2007-05-12 11:54:01 補充：
第一題只係我估姐~

2007-05-12 11:55:06 補充：
有十題~請閱讀題目

)第１題：好似計唔到
第２題：(x+2)(x-2)
第３題：(1+5x)(1-5x)
4.(7x+1)(7x-1)
5.(3a+4)(3a-4)
6.(4+2y)(4-2y)
7.

2007-05-11 20:30:58 補充：
上臉個２個人：第１題佢係問y^2 6x 9唔係問ｙ＾２＋６ｙ＋９請閱讀題目