问题 解答题
8.25=0.4:x
1
2
1
5
=x:4
4.2
x
=
2
5
14.4
0.5
=
x
8.4
答案

(1)8.25=0.4:x,

8.25x=0.4,

8.25x÷8.25=0.4÷8.25,

x=

8
165

(2)

1
2
1
5
=x:4,

1
5
x=
1
2
×
4,

1
5
x÷
1
5
=2÷
1
5

x=10;

(3)

4.2
x
=
2
5

2x=4.2×5,

2x÷2=21÷2,

x=10.5;

(4)

14.4
0.5
=
x
8.4

0.5x=14.4×8.4,

0.5x÷0.5=120.96,

x=241.92.

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