问题 解答题
解密码.
1-
3
4
X=
1
3
3×2.5-3X=5.74X+2.8×2=7.4
2
3
3
4
=
4
9
答案

(1)1-
3
4
X=
1
3

1-

3
4
X+
3
4
X=
1
3
+
3
4
X,

1
3
+
3
4
X=1,

1
3
+
3
4
X-
1
3
=1-
1
3

3
4
X=
2
3

3
4
X÷
3
4
=
2
3
÷
3
4

X=

8
9

(2)3×2.5-3X=5.7,

7.5-3X=5.7,

7.5-3X+3X=5.7+3X,

5.7+3X=7.5,

5.7+3X-5.7=7.5-5.7,

3X=1.8,

3X÷3=1.8÷3,

X=0.6

(3)4X+2.8×2=7.4,

4X+5.6=7.4,

4X+5.6-5.6=7.4-5.6,

4X=1.8,

4X÷4=1.8÷4,

X=0.45,

(4)

2
3
3
4
=
4
9

2
3
3
4
×
3
4
=
4
9
×
3
4

2
3
X=
1
3

2
3
X÷
2
3
=
1
3
÷
2
3

X=

1
2

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