问题 解答题
解方程.
3x÷
1
2
=
3
8
x:
1
7
=49
1
3
×
5
2
=
5
9
2x+30%x=9.2.
答案

(1)3x÷

1
2
=
3
8

3x÷

1
2
×
1
2
=
3
8
×
1
2

3x÷3=

3
16
÷3,

x=

1
16

(2)x:

1
7
=49,

1
7
×
1
7
=49×
1
7

x=7;

(3)x×

1
3
×
5
2
=
5
9

5
6
x=
5
9

5
6
6
5
=
5
9
×
6
5

x=

2
3

(4)2x+30%x=9.2,

2.3x=9.2,

2.3x÷2.3=9.2÷2.3,

x=4.

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