问题 解答题
解方程:
1
4
+2x=
1
2
72
100
×3-7x=1.04
1
2
x-1-
1
3
x=2
x-
2
9
x=14
3x-
3
4
x=
18
19
x
72
=
0.26
2.4
1.2:
2
3
=
x
5
18
x
=
3
10
3
15
1
20
1
5
=x:0.8
3
4
=
5
6
+1
答案

(1)

1
4
+2x=
1
2

1
4
+2x-
1
4
=
1
2
-
1
4

2x=

1
4

2x÷2=

1
4
÷2,

x=

1
8

(2)

72
100
×3-7x=1.04,

2.16-7x=1.04,

2.16-7x-1.04=1.04-1.04,

1.12-7x=0,

7x÷7=1.12÷7,

x=0.16;

(3)

1
2
x-1-
1
3
x=2,

1
6
x-1=2,

1
6
x-1+1=2+1,

1
6
x=3,

1
6
x÷
1
6
=3÷
1
6

x=18;

(4)x-

2
9
x=14,

7
9
x=14,

7
9
x÷
7
9
=14÷
7
9

x=18;

(5)3x-

3
4
x=
18
19

9
4
x=
18
19

9
4
x÷
9
4
=
18
19
÷
9
4

x=

8
19

(6)

x
72
=
0.26
2.4

2.4x=72×0.26,

2.4x=18.72,

2.4x÷2.4=18.72÷2.4,

x=7.8;

(7)1.2:

2
3
=
x
5

2
3
x=1.2×5,

2
3
x=6,

2
3
x÷
2
3
=6÷
2
3

x=9;

(8)

18
x
=
3
10
3
15

3
10
x=18×
3
15

3
10
x=
18
5

3
10
x÷
3
10
=
18
5
÷
3
10

x=12;

(9)

1
20
1
5
=x:0.8,

1
5
x=
1
20
×0.8,

1
5
x÷
1
5
=0.04÷
1
5

x=0.2;

(10)x÷

3
4
=
5
6
+1,

x÷

3
4
×
3
4
=
11
6
×
3
4

x=1

3
8

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