问题 解答题
解比例或方程:
5-
2
3
X=
1
3

2X+40%X=7.2
5(X-
1
3
)=2
4:
2
3
=
Χ
25
答案

(1)5-

2
3
X=
1
3

5-

2
3
X+
2
3
X=
1
3
+
2
3
X,

1
3
+
2
3
X=5,

1
3
+
2
3
X-
1
3
=5-
1
3

2
3
X=
14
3

2
3
3
2
=
14
3
×
3
2

X=7;

(2)2X+40%X=7.2,

(2+0.4)X=7.2,

2.4X=7.2,

2.4X÷2.4=7.2÷2.4,

X=3;

(3)5(X-

1
3
)=2,

5X-

5
3
=2,

5X-

5
3
+
5
3
=2+
5
3

5X=

11
3

5X÷5=

11
3
÷5,

X=

11
15

(4)4:

2
3
=
x
25

2
3
X=4×25,

2
3
3
2
=100×
3
2

X=150.

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