问题 解答题
求未知数.
(1)
1
3
x+
2
5
x=
4
15

(2)
0.25
x
=
1.25
3

(3)4x+3×0.7=6.5.
答案

(1)

1
3
x+
2
5
x=
4
15

11
15
15
11
=
4
15
×
15
11

x=

4
11

(2)

0.25
x
=
1.25
3

1.25x=0.25×3,

1.25x÷1.25=0.25×3÷1.25,

x=0.6;

(3)4x+3×0.7=6.5

4x+2.1=6.5,

4x+2.1-2.1=6.5-2.1,

4x÷4=4.4÷4,

x=1.1.

填空题
单项选择题