问题 解答题
求未知数X.
①4×6-0.4X=2.4
1
5
1
20
=
5
3
:X.
答案

(1)4×6-0.4X=2.4,

24-0.4x+0.4=2.4+0.4x,

24-2.4=2.4+0.4x-2.4,

21.6÷0.4=0.4x÷0.4,

x=54;

(2)

1
5
1
20
=
5
3
:X,

1
5
x=
1
20
×
5
3

1
5
x=
1
12

1
5
x÷
1
5
=
1
12
÷
1
5

x=

5
12

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单项选择题