问题 解答题
解方程.
(1)X+
3
8
X=121
(2)5X-3×
5
21
=
5
7

(3)75%X-0.5X=76.
答案

(1)x+

3
8
x=121,

11
8
x=121,

11
8
8
11
=121×
8
11

x=88;

(2)5x-3×

5
21
=
5
7

5x-

5
7
=
5
7

5x-

5
7
+
5
7
=
5
7
+
5
7

5x×

1
5
=
10
7
×
1
5

x=

2
7

(3)75%x-0.5x=76,

0.25x=76,

0.25x÷0.25=76÷0.25,

x=304.

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