问题 解答题
求未知数X.
2
3
X-
1
5
X=1   
1-
4
5
X=
1
3
   
1÷(
4
5
X-
1
5
)=3.
答案

2
3
X-
1
5
X=1 

7
15
X=1

7
15
15
7
=
15
7

X=2

1
7

②1-

4
5
X=
1
3
  

1+

4
5
X-
4
5
X=
1
3
+
4
5
X

4
5
X+
1
3
-
1
3
=1-
1
3

4
5
X=
2
3

4
5
5
4
=
2
3
×
5
4

X=

5
6

③1÷(

4
5
X-
1
5
)=3

1×(

4
5
X-
1
5
)÷(
4
5
X-
1
5
)=3×(
4
5
X-
1
5

 3×(

4
5
X-
1
5
)=1

12
5
X-
3
5
=1

12
5
X+
3
5
-
3
5
=1+
3
5

12
5
X=
8
5

12
5
5
12
=
8
5
×
5
12

X=

2
3

判断题
问答题