maths

Simplify

1. 5a/9 x 6/a^2 = 10/(3a)
2. The question should be wrong
3. (9-p)/(4p-36) = (9-p)/4(p-9) = -1/4
4. (x^3 - 8)/(6-3x) = (x-2)(x^2+2x+4)/3(2-x) = -(x^2+2x+4)/3

Factorize

1. m^3-n^3 = (m-n)(m^2+mn+n^2)
2. a^6+b^9 = (a^2)^3 + (b^3)^3 = (a^2+b^3)(a^4-a^2xb^3+b^6)

1. m^3-n^3 =?
m^3-n^3
=(m-n)(m^2+mn+n^2)

1. 5a/9 x 6/a^2 =?
= 5/3 x 2/a
= 10/(3a)

simplify

1. 5a/9 x 6/a^2
= 5/3 x 2/a
= 10/(3a)

simplify

1. 5a/9 x 6/a^2 =?
= 5/3 x 2/a
= 10/(3a)

2008-11-04 00:09:36 補充：
請看"意見"

2008-11-04 00:12:53 補充：
2. 8a/3b^2 x 15/x^2-4 =? 呢條好似怪怪地.... 係咪寫錯?!?!?!
3. 9-p/ 4p-36 =? 條問題係咪應該係
(9-p) / (4p-36) ??? = (9-p) / [4(p-9)] = (9-p) / [-4(9-p)] = -1/4

2008-11-04 00:14:11 補充：
4. 條問題係咪應該係 (x^3-8) / (6-3x) ????
= {(x-2)^3 - [3(x^2)(-2) + 3(x)(-2)^2]} / [3(2-x)]
= [(x-2)^3 + 6x(x-2) ] / [-3(x-2)] = {(x-2)[(x-2)^2+6x]} / [-3(x-2)]
= [(x-2)^2+6x] / (-3) = (x^2-4x+4+6x) / (-3) = (x^2+2x+4) / (-3)
= (x+2)^2 / (-3) = -(x+2)^2 / 3

2008-11-04 00:14:29 補充：
factorise
1. m^3-n^3
= (m-n)^3 - [3(m)^2(-n)+3(m)(-n)^2]
= (m-n)^3 + 3mn(m-n)
= (m-n)[(m-n)^2+3mn)]
= (m-n)(m^2-2mn+n^2+3mn)
= (m-n)(m^2+mn+n^2)

2008-11-04 00:14:41 補充：
2. a^6+b^9
= (a^2)^3+(b^3)^3
= (a^2+b^3)^3 - [3(a^2)^2(b^3)+3(a^2)(b^3)^2]
= (a^2+b^3)^3 - 3(a^2)(b^3)(a^2+b^3)
= (a^2+b^3)[(a^2+b^3)^2 - 3(a^2)(b^3)]
= (a^2+b^3)[a^4 + 2(a^2)(b^3) + b^6- 3(a^2)(b^3)]
= (a^2+b^3)[a^4 - (a^2)(b^3) + b^6]

2008-11-04 00:15:31 補充：
sorry.... 因為太多同太長... 要分幾次補答... 希望可以幫到你啦...