1)12x square+12x+ 3, 2)11-99b square,3)5x square-80y square

12x^2 + 12x + 3
=3(4x^2+4x+1)
=3(2x+1)^2

11-99b^2
=11(1-9b^2)
=11(1-3b)(1+3b)

5x^2-80y^2
=5(x^2-16y^2)
=5(x-4y)(x+4y)

2007-10-11 23:59:04 補充：
detailsQ1 4x^2 = (2x)^24x = 2(2x)(1)Q29b^2 = (3b)^2Q316y^2 = (4y)^2Rule of thumbWhen dealing with these questions, pick out the common factor first and then factorize!!

2007-10-12 00:09:52 補充：
Common factorization formulaexpansion------ factorization(a^2 - b^2) = (a "add" b)(a -b)a^2 "add" 2ab "add" b^2 = (a "add" b)^2a^2 - 2ab "add" b^2 = (a - b)^2

2007-10-12 00:10:53 補充：
Common factorization formulaexpansion------ factorizationa^3 'add' b^3 = (a 'add' b)(a^2 - ab 'add' b^2)a^3 - b^3 = (a - b)(a^2 'add' ab 'add' b^2)

(1) (6x+3)(2x+1)
(2) 11(1-9b square)= 11( 1+3b)(1-3b)
(3)5( x square -16x square)= 5(x-4x)(x+4x)

* (2), (3) 用左 a square -b square = (a+b)(a-b)

12x^2+12x+3
=(3x+1)(4+3)


11- 99b^2
=99b^2 - 11
=11(9b^2 - 1)
=11(3b+1)(3b-1)

5x^2 - 80y^2
=5(x^2 - 16y^2)
=5(x-4y)(x+4y)

1) sol: 12x^2+12x+3 = (6x+3)(2x+1)

2) sol: 11-99b^2 = 11-11．9b^2 = 11(1-9b^2) = 11(1-3b)(1+3b)

3) sol: 5x^2-80y^2 = 5(x^2-16y^2) = 5(x-4y)(x+4y)

2007-10-12 00:01:24 補充：
第1題...(6x 3)(2x 1)=3(2x 1)^2