问题 解答题
解方程或比例:
1
8
X-1=0.2
X:
5
14
=21:
5
8

x:0.4=
3
10
12
5
答案

(1)

1
8
X-1=0.2,

1
8
X-1+1=0.2+1,

1
8
X=1.2,

1
8
1
8
=1.2÷
1
8

X=9.6,

(2)X:

5
14
=21:
5
8

5
8
X=
5
14
×21,

5
8
5
8
=
5
14
×21÷
5
8

X=

5
14
×21×
8
5

X=12;

(3)x:0.4=

3
10
12
5

12
5
x=0.4×
3
10

12
5
12
5
=0.4×
3
10
÷
12
5

x=0.4×

3
10
×
5
12

x=

1
20

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