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maths

bonnie

2011-05-22 8:32 am

Basic rational function simplifcation
1. 12a^3 b(x+y)^2 / 8ab^2(x+y)
2.y^2 - 25/y^2-10y+25
3.x-y /y-x
4.2(y-x)^2 / 6x-6y
5.(2x / 5y) X (y/6x)
6.(x^3/4x+8) / (x^4/4)
7. 6ab^2 / (1/4)a^2 b
8.2a+3b/8x+16 / 2a^2-2a+3ab-3b/x+2

更新1:

請問....第5題點計到1/30 ? 就算分母乘埋係30xy,分子都有個2 喎...

更新2:

仲有第8題點樣由呢part = (2a + 3b)(x + 2)/(8x + 16)(2a^2 - 2a + 3ab - 3b) 轉到呢part? = (2a + 3b)/[8(2a + 3b)(a -1)] 麻煩你說明一下/.\

回答 (1)

myisland8132

2011-05-22 8:42 am

✔ 最佳答案

1. 12a^3 b(x+y)^2 / 8ab^2(x+y)

= 3a^2 (x+y) / 2b

2.y^2 - 25/y^2-10y+25

= (y - 5)(y + 5)/(y - 5)^2

= (y + 5)/(y - 5)

3.x-y /y-x = -1

4.2(y-x)^2 / 6x-6y

= 2(y - x)^2/6(x - y)

= -(y - x)/3

5.(2x / 5y) X (y/6x)

= 1/30

6.(x^3/4x+8) / (x^4/4)

= 4x^3/(4x + 8)(x^4)

= 1/[x(x + 2)]

7. 6ab^2 / (1/4)a^2 b

= 24b/a

8.2a+3b/8x+16 / 2a^2-2a+3ab-3b/x+2

= (2a + 3b)(x + 2)/(8x + 16)(2a^2 - 2a + 3ab - 3b)

= (2a + 3b)/[8(2a + 3b)(a -1)]

= 1/[8(a - 1)]

2011-05-22 12:38:20 補充：
5 是 1/15 SORRY

8 (2a^2 - 2a + 3ab - 3b)

= 2a(a - 1) + 3b(a - 1)

= (2a + 3b)(a - 1)

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