有8絛數學唔識做(代數)(15分)

2006-10-25 7:44 am
1. 5x+35=80
2. -5y+35=-80
3. 7x+45=122
4. 7y-45=-122
5.x+3=-4
6.x+14=-7
7.y+31=-9
8.x-7=-2
(要有過程和答案)

回答 (11)

2006-10-25 7:51 am
✔ 最佳答案
1. 5x = 80 - 35
x = 45/5
x = 9

2. -5y = -80 - 35
y = -115/(-5)
y = 23

3. 7x = 122 - 45
x = 77/7
x = 11

4. 7y = -122 + 45
y = -77/7
y = -11

5. x = -4 - 3
x = -7

6. x = -7 - 14
x = -21

7. y = -9 - 31
y = -40

8. x = -2 + 7
x = 5
2006-10-25 7:56 am
1, 5x+35=80
5x=80-35
5x=45
x=9

2, -5y+35=-80
5y=80+35
5y=115
y=23

3, 7x+45=122
7x=122-45
7x=77
x=11

4, 7y-45=-122
7y=122-45
7y=77
y=11

5, x+3=-4
x= -4-3
x=-7

6, x+14=-7
x=-7-14
x=-21

7, y+31=-9
y=-9-31
y=-40

8, x-7=-2
x=-2+7
x=7-2
x=5
2006-10-25 7:56 am
其實好易咋喎,
答你唔係問題,
只係.....總要自己學下呢~~

吾~~
俾少少hints你丫~

你試下先將冇代數果d計左先,
即係例如
(1) 5x+35 = 80
你先諗下點樣將個 +35 簡化,
+35 可以調去 80 果邊架,
由 + 變 -.....

咁你調左個35過去計完再 將 5x 簡化~
就ok架喇~~

2. -5y+35=-80
呢題又係先移走個 35 先,
之後兩邊都係 - 嘛,
咁咪可以約左佢,
咁5y 再簡化就ok~

3. 7x+45=122
先移走個 45,(記住 + 變 -, - 變+ 呀)~~
之後7x簡化~


4. 7y-45=-122
先移個 -45,
再簡化 7y


5.x+3=-4
先移3,
就知道答案喇~


6.x+14=-7
就咁移個14過去~ (本來+移過去就變-呀, 記住呵!)
就得到答案喇~


7.y+31=-9
又係移個31過去,
就知道答案~


8.x-7=-2
呢題要移 -7 呀,
本來 -7, 移過去 - 又要變 + 呀~~


其實真係幫你做唔係問題,
只係真係自己試下做會好d~~

可能你會覺得我多事,
不過真係為你好先咁做~

2006-10-24 23:57:46 補充:
其實我都覺得大家咁詳細寫答案,係害左佢~因為相信呢位小朋友一定就咁抄哂d答案,唔會自己再諗下計下咁,到第時測驗考試都係唔識!
2006-10-25 7:54 am
1. 5x+35=80
5x=80-35
x=45/5
x=9

2. -5y+35=-80
-5y=-80-35
y=-115/(-5)
y=23

3. 7x+45=122
7x=122-45
x=77/7
x=11

4. 7y-45=-122
7y=-122+45
y=-77/7
y=-11

5.x+3=-4
x=-4-3
x=-7

6.x+14=-7
x=-7-14
x=-21

7.y+31=-9
y=-9-31
y=-40

8.x-7=-2
x=-2+7
x=5
2006-10-25 7:53 am
1. 5x+35=80
 5x=80-35
 5x=45
 x=45/5
 x=9

2. -5y+35=-80
 35+80=5y
 115=5y
 y=115/5
 y=23

3. 7x+45=122
 7x=122-45
 7x=77
 x=77/7
 x=11

4. 7y-45=-122
 7y=45-122
 7y=-77
 y=-77/7
 y=-11

5. x+3=-4
 x=-4-3
 x=-7

6. x+14=-7
 x=-7-14
 x=-21

7. y+31=-9
 y=-9-31
 y=-40

8. x-7=-2
 x=-2+7
 x=5
2006-10-25 7:53 am
1. 5x = 80 - 35
5x = 45
x = 9

2. 5y = 35 + 80
5y = 115
y = 23

3. 7x = 122 - 45
7x = 77
x = 11

4. 7y = -122 + 45
7y = -77
y = -11

5. x = -4 - 3
x = -7

6. x = -7 - 14
x = -21

7. y - = 9 - 31
y = -40

8. x = -2 + 7
x = 5
2006-10-25 7:53 am
1. 5x+35=80
5x=80-35
5x=45
x=9
2. -5y+35=-80
-5y=-80-35
-5y=-115
y=23
3. 7x+45=122
7x=122-45
7x=77
x=11
4. 7y-45=-122
7x=-122+45
7x=-77
x=-11
5.x+3=-4
x=-4-3
x=-7
6.x+14=-7
x=-7-14
x=-21
7.y+31=-9
y=-9-31
y=-40
8.x-7=-2
x=-2+7
x=5
下次自己做!!!!
2006-10-25 7:53 am
咁簡單都要問......
幫你 = 害左你

請各位吾好答佢 !!!

2006-10-24 23:54:31 補充:
oh shit ................ post 遲左 !!!!
2006-10-25 7:52 am
1. 5x+35=80
5x=80-35
5x=45
x=9

2. -5y+35=-80
-5y= -80-35
-5y= -115
5y=115
y=23

3. 7x+45=122
7x=122-45
7x=77
x=11

4. 7y-45=-122
7y=-122+45
7y= -77
y= -11

5.x+3=-4
x= -4-3
x= -7

6.x+14=-7
x= -7-14
x= -21

7.y+31=-9
y= -9-31
y= -40

8.x-7=-2
x= -2+7
x=5
2006-10-25 7:52 am
1. 5x + 35 = 80
5x = 80-35
5x = 45
x = 45 / 5
x = 9

2. -5y+35=-80
80 +35 = 5y
115 = 5y
y = 115/5
y = 23

3. 7x+45=122
7x = 122-45
7x = 77
x = 77/7
x =11

4. 7y-45=-122
7y = -122+45
7y = -77
y = -77/7
y = -11

5. x+3=-4
x = -4-3
x = -7

6.x+14=-7
x = -7-14
x = -21

7.y+31=-9
y = -9 - 31
y = - 40

8.x-7=-2
x = -2 + 7
x = 5


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