數學-解方程 中一題

2007-11-07 5:15 am
1;] 5=9+6-2x

2;] 4+3n-12=25

3;] 11-7y+3= -7(負7)

*4;] 5h+1-4h=10

*5;] 6m-11m+2=22


*同時出現2個未知數應該點處理`?!

同埋上面哦d點計=v= 十萬個THX<3

回答 (9)

2007-11-07 5:39 am
✔ 最佳答案
1]5=9+6-2x
2x=9+6-5
2x=10
x=10/2
x=5

2]4+3n-12=25
4+3n=25+12
4+3n=37
3n=37-4
3n=33
n=33/3
n=11

3]11-7y+3= -7
-7y+3= -7-11
-7y+3= -18
-7y= -18-3
-7y= -21
y= -21/-7
y=3

4]5h+1-4h=10
h+1=10
h=10-1
h=9

5]6m-11m+2=22
-5m+2=22
-5m=22-2
-5m=20
m=20/-5
m=-4


*同時出現2個未知數應該點處理`?!
*咁就要睇下果兩個未知數係唔係同類項啦''
就好似 5h+1-4h
個1暫時唔好理佢.. 就變成..5h-4h
姐話5個h減左4個h..咁就剩返1個h
咁[[5h-4h=h]]啦

********lee個/號姐係除********

2007-11-06 21:42:37 補充:
我個答案詳細好多....仲有齊步驟tim....揀我啦~~~!!!!!!!!!!!!!! 唔該晒..''' ~^^~ '''
2007-11-07 6:36 am
1. 2x=15-5
x=5
2. 3n=41
n=41/3
3. -7y=-21
y=3
4. h=9
5. -5m=20
m=-4
參考: so easy...I am form 3 student
2007-11-07 5:39 am
1) 5=9+6-2x
5=15-2x
-10=2x
x=-5

2) 4+3n-12=25
3n-8=25
3n=33
n=11

3) 11-7y+3=-7
14-7y=-7
-7y=-21
y=3

4) 5h+1-4h=10
h=9

5) 6m-11m+2=22
-5m=20
m=-4

兩邊同時出現未知數,只要好似多項式咁搵晒d 同類項出黎,
調去另一邊( 前面有+號就變-號, x號變除號,如此類推,總之相反)
跟住兩邊計埋晒, 通常就會出到答案.
參考: i am form1 too.
2007-11-07 5:31 am
我都唔知點解俾你聽好,你睇下我點做,睇下明唔明啦,唔明就sd e-mail問我啦 ;) 隨時歡迎

1. 5=9+6-2x
2x=9+6-5
2x=10
x=5
2. 4+3n-12=25
4+3n=25+12
4+3n=37
3n=37-4
3n=33
n=11
3. 11-7y+3= -7
11-7y= -7-3
-7y= -21
y= -21/-7
y=3
4. 5h+1-4h=10
5h-4h=10-1
h=9
5. 6m-11m+2=22
6m-11m=22-2
-5m=20
m=20/-5
m= -4
參考: 自己
2007-11-07 5:29 am
1) 5=9+6-2X
2X=9+6-5
2X=10
X=5

2) 4+3n-12=25
3n=33
n=11

3) 11-7y+3= -7
11-7=-10
-7y=-21
y=3

4)一樣既未知數可以相加或相減
5h+1-4h=10
h+1=10
h=9
5) 6m-11m+2=22
-5m+2=22
-5m=20
m=-4
參考: 自己
2007-11-07 5:28 am
1. 5=9+6-2x
2x=9+6-5
2x=10
x=5

2.4+3n-12=25
3n=25+12-2
3n=35
n=11/2/3 or 11.66666667

3.11-7y+3=-7
11+3+7 =7y
21=7y
3=y

4.5h+1-4h=10
h=10-9
h=1

5.6m-11m+2=22
-5M=22-2
-20=5M
-4=M

2007-11-06 21:30:20 補充:
4.5h 1-4h=10h=10-1h=9
參考: ME
2007-11-07 5:28 am
1;] 5=9+6-2x
2x=9+6-5
x=10/2=5

2;] 4+3n-12=25
3n=25+12-4
n=33/3=11

3;] 11-7y+3= -7(負7)
7y=11+3+7
y-21/7=3

*4;] 5h+1-4h=10
h=10-1=9

*5;] 6m-11m+2=22
-5m+2=22
-5m=20
m=-4

同時出現2個未知數若要計, 就一定有2條方程
2007-11-07 5:25 am
1;] 5=9+6-2x
5=15-2x
2x=10
x=5

2;] 4+3n-12=25
3n-8=25
3n=33
n=11

3;] 11-7y+3= -7
14-7y=-7
7n=7
n=1

*4;] 5h+1-4h=10
h+1=10
h=9

*5;] 6m-11m+2=22
2-5m=22
-5m=20
m=-4
參考: myself
2007-11-07 5:23 am
1.-2x=-10
x=5
2.3n=33
n=11
3.-7y=-21
y=3
4.h=9
5.-5m=20
m=-4

2個未知數都係x既話都可以相減


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