问题 解答题
5:x=3:9
54
x
=
4
5
x:
1
4
=4:
2
3
36:18=x:5.4
6
1.5
=
x
10
1:
1
2
=x:
1
3
3
8
2
5
=x:
6
5
5
6
2
3
=
1
8
:x
5
12
=
7
x
7
2
:x=
3
5
1
7
1
10
1
8
=x:
1
4
x
0.8
=1.5:4
X:1.5=25%
x
13
=0.6
2.5
x
=
2
25
x:
3
4
=
8
9
答案

(1)5:x=3:9,

3x=5×9,

3x÷3=45÷3,

x=15;

(2)

54
x
=
4
5

4x=54×5,

4x÷4=270÷4,

x=67.5;

(3)x:

1
4
=4:
2
3

2
3
x=
1
4
×4,

2
3
x÷
2
3
=1÷
2
3

x=

3
2

(4)36:18=x:5.4,

18x=36×5.4,

18x÷18=194.4÷18,

x=10.8;

(5)

6
1.5
=
x
10

1.5x=6×10,

1.5x÷1.5=60÷1.5,

x=40;

(6)1:

1
2
=x:
1
3

1
2
x=1×
1
3

1
2
x÷
1
2
=
1
3
÷
1
2

x=

2
3

(7)

3
8
2
5
=x:
6
5

2
5
x=
3
8
×
6
5

2
5
x÷
2
5
=
9
20
÷
2
5

x=

9
8

(8)

5
6
2
3
=
1
8
:x,

5
6
x=
2
3
×
1
8

5
6
x÷
5
6
=
1
12
÷
5
6

x=

1
10

(9)

2
12
=
7
x

2x=12×7,

2x÷2=84÷2,

x=42;

(10)

7
2
:x=
3
5
1
7

3
5
x=
7
2
×
1
7

3
5
x÷
3
5
=
1
2
÷
3
5

x=

5
6

(11)

1
10
1
8
=x:
1
4

1
8
x=
1
10
×
1
4

1
8
x÷
1
8
=
1
40
÷
1
8

x=

1
5

(12)

x
0.8
=1.5:4,

4x=1.5×0.8,

4x÷4=1.2÷4,

x=0.3;

(13)X:1.5=25%,

X=1.5×25%,

X=0.375;

(14)

x
13
=0.6,

x=13×0.6,

x=7.8;

(15)

2.5
x
=
2
25

2x=2.5×25,

2x÷2=62.5÷2,

x=31.25;

(16)x:

3
4
=
8
9

x=

3
4
×
8
9

x=

2
3

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