早教吧 育儿知识 作业答案 考试题库 百科 知识分享

求未知数X.①548x-2=0.5②118:29=x:613③x8.1=410.8④X:12=74:2.8.

题目详情
求未知数X.
5
48
x-2=0.5
1
18
2
9
=x:
6
13

x
8.1
=
4
10.8

④X:12=
7
4
:2.8.
▼优质解答
答案和解析
(1)
5
48
x-2=0.5,
5
48
x-2+2=0.5+2,
5
48
x ÷
5
48
=2.5 ÷
5
48

x=24;

(2)
1
18
2
9
=x:
6
13

2
9
x=
1
18
×
6
13

2
9
x ÷
2
9
=
1
39
÷
2
9

x=
3
26


(3)
x
8.1
=
4
10.8

10.8x=8.1×4,
10.8x÷10.8=32.4÷10.8,
x=3;

(4)X:12=
7
4
:2.8,
2.8x=12×
7
4

2.8x÷2.8=21÷2.8,
x=7.5.