问题 解答题
解方程.
X+
3
8
X=121
5X-3×
5
21
=
5
7
2
3
1
4
=12.
答案

(1)X+

3
8
X=121,

11
8
X=121,

11
8
X÷
11
8
=121÷
11
8

X=88,

(2)5X-3×

5
21
=
5
7

5X-

5
7
=
5
7

5X-

5
7
+
5
7
=
5
7
+
5
7

5X=

10
7

5X÷5=

10
7
÷5,

X=

2
7

(3)

2
3
1
4
=12,

2
3
1
4
×
1
4
=12×
1
4

2
3
X=3,

2
3
X÷
2
3
=3÷
2
3

X=

9
2

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