１２． 6x－５(1-2x)小過／等於２
１３． 5份之4(3x-8)大過／等於２
１４． ４份之３(2x-1)-5大過／等於４份之５(x-3)
１６．
Amy has y stamps. After using 3 of them, she has fewer than 10 stamps left. Find the greatest possible value of y.
１７．
If 2 times the sum of two consecutive even numbers is greater than 94, what is the smallest possible value of the larger number?
請用英文答！！！
maths
2009-02-13 3:18 am
回答 (1)
2009-02-13 7:32 am
✔ 最佳答案
12.6x - 5(1 - 2x) ≤ 2
6x - 5 + 10x ≤ 2
16x - 5 ≤ 2
16x - 5 + 5 ≤ 2 + 5
16x ≤ 7
x ≤ 7/16
13.
(4/5)(3x - 8) ≥ 2
5 x (4/5)(3x - 8) ≥ 5 x 2
4(3x - 8) ≥ 10
4(3x - 8)/4 ≥ 10/4
3x - 8 ≥ 5/2
3x - 8 + 8 ≥ (5/2) + 8
3x ≥ 21/2
3x x (1/3) ≥ (21/2) x (1/3)
x ≥ 7/2
14.
(3/4)(2x - 1) - 5 ≥ (5/4)(x - 3)
4x(3/4)(2x - 1) - 4x5 ≥ 4x(5/4)(x - 3)
3(2x - 1) - 20 ≥ 5(x - 3)
6x - 3 - 20 ≥ 5x - 15
6x - 23 ≥ 5x - 15
6x - 23 - 5x + 23 ≥ 5x - 15 - 5x + 23
x ≥ 8
16.
y - 3 < 10
y - 3 + 3 < 10 + 3
y < 13
The greatest possible value of y is 12.
17.
Let the larger even number be n.
Then, the smaller even number = n - 2
2[n + (n - 2)] > 94
2[n + n - 2] > 94
2(2n - 2) > 94
4(n - 1) > 94
4(n - 1)/4 > 94/4
n - 1 > 23.5
n - 1 + 1 > 23.5 + 1
n > 24.5
The smallest possible value of the larger even number is 26.
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收錄日期: 2021-04-29 18:16:45
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20090212000051KK01386