Question

Aflati x din proportiile:

1) 11/2+x=33/7
2) 21/5=3x/0,15
3)4,6/0,(3)=8/4x

4)24/5x-2=3
5)x/3a=16-9/40 unde 3a se divide cu 8.

Answer 1

1)11/2+x=33/7
x=33/7-11/2
x=(33·2-11·7)/14
x=(66-77)/14=-11/14

2)21/5=3x/0,15
3x/1:15/100=21/5
3x/1·100/15=21/5
300x/15=21/5
300x·5=21·15
1500x=315
x=315/1500 simplif.cu 5=63/300=simplif.cu 3=21/100

3)0,(3)=3/9
46/10:3/9=8/4x
46/10·9/3=8/4x
46/10·3/1=2/x
138/10=2/x
138x=2·10
x=20/138=simplif cu 2=10/69

4)24/(5x-2)=3
24=3(5x-2)
24=15x-6
-15x=-6-24
-15x=-30     (-1)
x=30/15
x=2