一元一次的方程 ... 緊急

1.
5x-3 = 2x-3
5x+3=2x-3+3
5x-2x=2x-2x
3x=0
x=0

2.
17+7y-y = 1+2y
17+6y-2y-1=1+2y-2y-1
4y+16-16=0-16
4y÷4=-16÷4
y=-4

3.
-3b+49 = 21+5b+6b
-3b+49-5b-6b-49 = 21+5b+6b-5b-6b-49
-3b-5b-6b=--49+21
-14b÷-14=-28÷-14
b=2

5.
4(2t-5) = 2t-2
8t-20-2t+2 = 2t-2-2t+2
6t-18+18=0+18
6t÷6=18÷6
t=3

6.
5(m+3) = 2(2m-7)
5m+15-15-4m=4m-14-15-4m
m=-29

7.
2p-3(p+5) = 5p-21
2p-3p-15-5p+15=5p-21-5p+15
2p-3p-5p=-21+15
-6p÷-6=-6÷-6
p=1

8.
15-(r-6) = 6-(3r+5)
15-r+6+3r-15-6=6-3r-5+3r-15-6
-r+3r=6-6-5-15
-2r÷-2=-20÷-2
r=10

9.
(y+7)/5 = 3y
[(y+7)/5](5)=(3y)(5)
y+7-y=15y-y
14y=7
y=7/14
y=1/2 (即2分之1)

10.
(u-5)/2=(1+u)/4
(u-5)/2-(1+u)/4=(1+u)/4-(1+u)/4
{[2(u-5)- (1+u)]/4}(4)=(0)(4)
2u-10-1-u=0
u-11+11=0+11
u=11

希望能幫到你，如仍有疑問，請給我電郵，大家交個朋友！

2008-10-20 08:53:32 補充：
對不起, 第1題的第2個步有漏, 現修正如下:
1.
5x-3 = 2x-3
5x-3+3=2x-3+3
5x-2x=2x-2x
3x=0
x=0

最尾個兩條都5係式完全5明!
1.5x-3 = 2x-3
5x=2x-3+3
5x-2x=0
3x=0 x=0

2. 17+7y-y = 1+2y
17+6y=1+2y
4y=-16
y=-4

3. -3b+49 = 21+5b+6b
-3b-5b-6b=-49+21
-14b=-28
b=2

5. 4(2t-5) = 2t-2
8t-20-2t+2=0
6t=18
t=3

6. 5(m+3) = 2(2m-7)
5m+15=4m-14
1m=-29 m=-29

7. 2p-3(p+5) = 5p-21
2p-3p-15=5p-21
2p-3p-5p=-21+15
-6p=-6
p=1

8. 15-(r-6) = 6-(3r+5)
15-r+6=6-3r-5
-r+3r=6-6-5-15
-2r=-20
r=10

希望可以幫到你
最尾個兩條真係唔知你咩意思， sorry

1.5x-3 = 2x-3
5x=2x-3+3
5x-2x=0
3x=0 x=0

2. 17+7y-y = 1+2y
17+6y=1+2y
4y=-16
y=-4

3. -3b+49 = 21+5b+6b
-3b-5b-6b=-49+21
-14b=-28
b=2

5. 4(2t-5) = 2t-2
8t-20-2t+2=0
6t=18
t=3

6. 5(m+3) = 2(2m-7)
5m+15=4m-14
1m=-29 m=-29

7. 2p-3(p+5) = 5p-21
2p-3p-15=5p-21
2p-3p-5p=-21+15
-6p=-6
p=1

8. 15-(r-6) = 6-(3r+5)
15-r+6=6-3r-5
-r+3r=6-6-5-15
-2r=-20
r=10