方程式....(數學.非常easy)!

2008-10-18 7:13 pm

以下幾條方程式.睇下大家識唔識:
1) 8a+(3a-7/2)=6
2) 3/4y=1-1/2y
3) 2s/3-1=s+2/5
我想要每題既過程! 仲有答案...唔該大家識做個d幫幫我手!!
+=加 - =減 x=乘 =除 <<<代表符號!!!
*唔同顏色代表唔同部份...有d分數打唔到所以用左" / "黎代替!

更新1:

1題都得嫁啦...總之識1題都打啦...thank you!

更新2:

第1位回答既人: 1題岩... 其實(3a-7/2)唔係3a減7/2 係3a 同 7係分子.....2係分母!! 所以你搞錯左.... **如果你見到...你可以再改番..[唔知得唔得!]

回答 (3)

2008-10-20 8:57 pm

✔ 最佳答案

1) 8a+(3a-7/2)=6

8a+(6a-7)/2=6
16a+6a-7=12
22a=19
a=19/22

2) 3/4y=1-1/2y
3/4y=(2y-1)/2y
3=-1x4y
4=4y
1=y

3) 2s/3-1=s+2/5

(2s-3)/3=(5s+2)/5
(2s-3)x5=(5s+2)x3
10s-15=15s+6
-21=5s
-21/5=s

希望沒有錯啦

2008-10-20 12:59:33 補充：
3) 2s/3-1=s+2/5

(2s-3)/3=(5s+2)/5
(2s-3)x5=(5s+2)x3
10s-15=15s+6
-21=5s
-21/5=s
S=負4又1分之5

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2008-10-18 11:36 pm

1)
8a+3a-7/2 = 6
11a-7/2 = 6
22a-7 = 12
22a = 19
a = 19/22

2)
3/4y = 1-1/2y
3 = 4-2y
2y = 1
y = 1/2

3)
2s/3 - 1 = s+2/5
10s - 15 = 15s + 6
-5s = 21
s = -21/5

2008-10-18 15:41:44 補充：
2)
3/4y = 1-1/2y
3y = 4 - 2y
y = 4/5

sorry,第二條少個y

參考: 自己

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かや

2008-10-18 7:30 pm

8a+3a-3.5=6
8a+3a=9.5
11a=9.5
a=9.5/11
a=95/110

3/4y+1/2y=1
1/1/4y=1
y=4/5

2s/3=s+1/2/5
2s=3s+4/2/5
2s-3s=4/2/5
-s=4/2/5
s=-4/1/5

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收錄日期: 2021-04-19 12:44:00
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