问题 解答题
x+
3
14
=
13
21

x-(
2
5
+
1
3
)=
7
30
答案

(1)x+

3
14
=
13
21

x+

3
14
-
3
14
=
13
21
-
3
14

x=

17
42

(2)x-(

2
5
+
1
3
)=
7
30

x-

11
15
=
7
30

x-

11
15
+
11
15
=
7
30
+
11
15

x=

29
30

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