數學題4(中學生請回答)

1.2a+7=13
2a=6
a=3

2.4b-5=-21
4b=-16
b=-4

3.59-3d=2
-3d=-57
d=19

4.5=9+6-2x
5=15-2x
2x=10
x=5

5.2(2x-1)=6
4x-2=6
4x=8
x=2

2006-10-16 20:57:52 補充：
唔夠詳細的話...可再參考:1.2a+7=132a=13-72a=6a=6÷2a=32.4b-5=-214b=-21+54b=-16b=-16÷4b=-43.59-3d=2-3d=2-59-3d=-57d=-57÷-3d=194.5=9+6-2x5=15-2x5-15=-2x-10=-2x-10÷-2=x5=x / x=55.2(2x-1)=64x-2=64x=6+24x=8x=8÷4x=2

1) 2a + 7 = 13
2a = 6
a = 3

2) 4b - 5 = -21
4b = -16
b = -4

3) 59 - 3d = 2
59 - 2 = 3d
3d = 57
d = 19

4) 5 = 9 + 6 -2x
2x = 9 + 6 - 5
2x = 10
x = 5

5) 2(2x - 1) = 6
2x - 1 = 3
2x = 3 + 1
2x = 4
x =2

1.2a+7 =13
2a+7-7=13-7
2a = 6
2.4b-5=-21
4b =-21+5
4b =-16
b =-4
3.59-3d=2
-3d =2-59
-3d =-57
d =19
4 .5=9+6-2x
9+6-2x=5
-2x =5-6-9
-2x =-10
x =5
5.2(2x-1)=6
2x-1 =6除2
2x-1 =3
2x =4
x =2

1.2a+7=13
2a+7-7=13-7
2a=6
2a除2=6除2
a=3

2.4b-5=21
4b-5+5=21+5
4b=26
4b除4=26除4
b=6.5

3.59-3d=2
3d=-57
d=19

4.5=9+6-2x
5=15-2x
2x=10
x=5

5.2(2x-1)=6
4x-2=6
4x=8
x=2

1. 2a + 7 = 13
2a = 13 - 7
2a = 6
a = 3

2. 4b - 5 = - 21
4b = - 21 + 5
4b = - 16
b = - 4

3. 59 - 3d = 2
- 3d = 2 - 59
- 3d = - 57
d = 19

4. 5 = 9 + 6 - 2x
- 2x = 5 - 9 - 6
- 2x = - 10
x = 5

5. 2 (2x - 1) = 6
2x - 1 = 3
2x = 4
x = 2

2a+7=13
2a+7-7=13-7
2a=6
2a/2=3
a=3

4b-5=-2
4b-5+5=-2+5
4b/4=3/
b=0.75

59-3d=2
59-3d+3d=2+3d
59-2=2+3d-2
57=3d
57/3=3d/3
19=d
d=19

5=9+6-2x
5+2x= 9+6-2x+2x
5+2x-5=15-5
2x=10
2x/2=10/2
x=5

2(2x-1)=6
2(2x-1)/2=6/2
2x-1=3
2x-1+1=3+1
2x=4
2x/2=4/2
x=2

1. 2a+7=13
2a=13-7
2a=6
a=3
2. 4b-5=-21
4b= -21-(-5)
4b= -16
b= -4
3. 59-3d=2
-3d=2-59
-3d=-57
d=19
4. 5=9+6-2x
5-15=-2x
-10=-2x
5=x
x=5
5. 2(2x-1)=6
4x-2=6
4x=8
x=2

1)
2a+7=13
2a=6
a=3

2)
4b-5= -21
4b= -16
b= -4

3)
59-3d=2
3d+2=59
3d=57
d=19

4)
5=9+6-2x
9-2x= -1
-1+2x=9
2x=10
x=5

5)
2(2x-1)=6
2x-1=3
2x=4
x=2

1.2a+7=13
2a=6
a=3

2.4b-5=-21
4b=-16
b=-4

3.59-3d=2
3d=57
d=19

4. 5=9+6-2x
2x=10
x=5

5.2(2x-1)=6
4x-2=6
4x=8
x=2

1)2a+7=13
2a=13-7
2a=6
a=3
2)4b-5=-21
4b=-21+5
4b=-16
b=-4
3)59-3d=2
-3d=2-59
-3d=-57
d=19
4)5=9+6-2x
5=15-2x
2x=10
x=5
5)2(2x-1)=6
2x-1=3
2x=4
x=2