F.3升F.4 maths questions 40 pts

[匿名]

2010-08-08 4:48 am

1. A) Factorize X^3-8
B) Using the result in (A), Factorize X^3-7x+6
(Hint: X^3-7x+6= X^3-8+_____)
2. The salary tax of Mosses this year is $7200. If he is entitled to $130000
allowance, find his total annual income.

更新1:

應課稅入息實額 $稅率稅款 %$ 最初的40,00040,000 2 800 800 其次的40,00080,000 72,8003,600 其次的40,000120,000124,8008,400 餘額17 稅款（按累進稅率計算） 40,000 按 2%計算 = 800 40,000 按 7%計算 = 2,800 40,000 按12%計算 = 4,800 餘下按17%計算 =

更新2:

Thanks!

更新3:

the salary tax rate

回答 (1)

匿名

2010-08-08 4:53 am

✔ 最佳答案

1. A) Factorize X^3-8
X^3 - 8
= X^3 - 2^3
= (X-2)(X^2 + 2X + 4)
B) Using the result in (A), Factorize X^3-7X+6
(Hint: X^3-7X+6= X^3-8+_____)
X^3-7X+6 = X^3 - 8 + 14 - 7X
=(X-2)(X^2 + 2X + 4) - 7(X-2)
=(X-2)(X^2 + 2X + 4-7)
=(X-2)(X^2 + 2X - 3)
=(X-2)(X-3)(X+1)
2. The salary tax of Mosses this year is $7200. If he is entitled to $130000
allowance, find his total annual income.
Can you list the salary tax rate?

2010-08-07 21:31:21 補充：
2. The salary tax of Mosses this year is $7200. If he is entitled to $130000
allowance, find his total annual income.
Let $x be his total annual income,
(x-130000-40000-40000)*12% = 7200-800-2800
(x-210000) = 30000
x = 240000
His annual income is $240000

2010-08-07 21:31:38 補充：
Thz for your information

參考: Hope can help you^^”

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