F.2Math !!Thx!

用戶18235

2009-04-27 3:11 am

1..Wendy started reading a book on Monday .On Tuesday, she read 4 pages more than that on monday. The total number of pages she read on these two days was 36.Find the number of pages she read on Monday.(Show your working)

2.Determine whether the point (8.-3) is on the straight line 3x +4y -12=0.
Explain your answer.

3.Change the subject of the foemula A=(a+b)h/2 to b.

4.Factorize 3a-2ab+6a^2-b

5.Divide $3960 in the ratio 2:5:4 Find the amount of the greatest portion.

6.Which is the best way to collect the information of the lifetimes of different brands of light bulbs?
A. IntervieW B. Questionnaire C. Discussion D. Experiment

7.Which kind of statistical graph is most suitable to compare the reading time of boys and girls?
A. Scatter diagram B. Pie chart C. Broken-line graph D. Back-to back stem-and-leaf diagram

回答 (1)

小鈴

2009-04-28 2:24 am

✔ 最佳答案

1. Let the number of pages Wendy read on Monday be x pages.
Then the number of pages she read on Tuesday will be (x+4) pages.

x + (x+4) = 36
2x = 32
x = 16
Therefore, Wendy read 16 pages on Monday.

2. Sub (8, -3) into the straight line:
L.H.S = 3(8) + 4(-3) -12
= 24 - 12 - 12
= 0 = R.H.S
Since it satisfies the equation, the point (8, -3) lies on the straight line 3x+4y-12=0.

3. A= (a+b)h/2
2A= (a+b)h
2A/h = a+b
b = 2A/h - a

4. 3a-2ab+6a^2-b
= 6a^2 + 3a - 2ab -b
= (6a^2 + 3a) - (2ab + b)
= 3a(2a + 1) - b(2a + 1)
= (2a+1) (3a - b)

5. Break $3960 into (2+5+4)= 11 equal groups
To satisfy the ratio 2:5:4, each will multiply by $110.
therefore, the greatest portion will be 5*110 = $550.

6. D. Experiment

7. C. Broken-line graph

第7題不肯定, 其他應該都ok的。
希望幫到你

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