1. There are some milk candies of 1.6g each and some coffee candies of 2.3g each in a pile of candies with weight od 88.6g. If all milk candies and coffee candies are grouped into packs of 3 and 2 respectively, then there are 19 packs of candies in total. How many candies are there?
2.a) Expand (2a+b)(2a+b)
2.b) By using the result of (a) ,expand (2p-2q+r)(2p-2q+r)
3.AB=DC=x,BC=BD=y+3,ED=x+1, and AE=x+2. If the perimeter of BD+DC+BC is 13 and the AB+AE+ED+BD is twice the perimeter of BD+DC+BC minus 4, by how much is x longer/shorter than y?
Thx........^.^
F2. maths
2010-08-24 1:37 am
回答 (2)
2010-08-24 2:06 am
✔ 最佳答案
Q1)1.6X+2.3Y=88.6 ... (1)
X/3 +Y/2 = 19 ... (2)
(1)*10 : 16x+23y = 886
(2)*48 : 16x+24y = 912
y = 26 x = 18
2a) (2a+b)(2a+b)=4a^2+8ab+b^2
b) (2p-2q+r)(2p-2q+r)
= [ 2(p-q)+r ][ 2(p-q) +r ]
using result in (a), put a = p-q and r = b
[ 2(p-q)+r ][ 2(p-q) +r ]
= 4(p-q)^2+8(p-q)(r)+r^2
3)
2(y+3)+x = 13 ... (1)
x+x+2+x+1+y+3 = 2*13 - 4 ... (2)
from(1), we have
x+2y = 7 ... (3)
from(2), we have
3x+y = 16
y = 16-3x ... (4)
put (4) into (3),
x+2(16-3x)=7
-5x=-25
x=5
y=1
x is longer than y 4 units
2010-08-24 4:16 am
Q1:
1.6x+2.3y=88.6
(x/3)+(y/2)=19
x:milk,y:coffee
1.6x+2.3y=88.6
(x/3)+(y/2)=19
x:milk,y:coffee
收錄日期: 2021-04-22 00:58:57
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https://hk.answers.yahoo.com/question/index?qid=20100823000051KK01389