F.2數學(20點

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Q 1 : It us known that the H.C.F of a given number and 63 is 9. Find two possible valuse of the given number.

A 1 : 9 or 18

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Q 2 : It is know that the L.C.M of a given number and 48 is 144. Find two possible valuse of the given number.

A 2 : 72 or 144

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Q 3 : (-3/21)÷（-39/42)

A 3 :

(-3/21) ÷ (-39/42)
= (-1/7) × (42/-39)
= -6/-39
= 6/39

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Q 4 : It is know that the product of 4.5 and y is not less than 9.

A 4 :

a) Formulate an inequality to represent the above relation.

4.5y > 9

b) Write down three integers that satisfy the inequality in question (a)

3 , 4 or 5

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Q 5 : In each of the following, a(n) is the general term of the sequence. Find the 1st term and the 5th term of the sequence.

A 5 :

a) a(n) = 6n-1

The first term : 6×1-1 = 5
The 5th term : 6×5-1 = 29

b) a(n) = 1/2n

The first term : 1/(2×1) = 1/2
The 5th term : 1/(2×5) = 1/10

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Q 6 : Andy has x books.The number of books that Cindy has is 2 times that of Andy while the number of books that Ken has is 5 less than Cindy

A 6 :

a)How many books does Cindy have?

Cindy has : 2x books .

b)How many books does Ken have?

Ken has : ( 2x - 5 ) books .

c)How many books do Cindy and Ken have altogether?

Cindy and Ken have : 2x + ( 2x - 5 ) = ( 4x - 5 ) books .

d)How many less books does Andy have then Ken?

The books Andy has less than Ken : 2x - 5 - x = ( x - 5 ) books .

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Please check the wording of question 5 (a)
a) a^n = 6n-1

2011-08-18 11:19:01 補充：
Question 3.
The fraction can be further reduced to 2/13