问题 解答题
解比例
49:(5+x)=14:20.8:x=
3
5
:0.75
45
8
=
2+x
0.8
3.2
7
=
x+8
5
x:3.6=
3.2
1.8
2
5
5
7
=x:
3
14
答案

(1)49:(5+x)=14:2

49×2=5×14+14x

98-70=70+14x-70

28÷14=14x÷14

x=2;

(2)0.8:x=

3
5
:0.75

3
5
x=0.8×0.75

3
5
x÷
3
5
=0.6÷
3
5

x=1;

(3)

45
8
=
2+x
0.8

45×0.8=8×2+8x

36-16=16+8x-16

20÷8=8x÷8

x=2.5;

(4)

3.2
7
=
x+8
5

3.2×5=7x+7×8

16-56=7x+56-56

-40÷7=7x÷7

x=-5

5
7

(5)x:3.6=

3.2
1.8

1.8x=3.6×3.2

1.8x÷1.8=11.52÷1.8

x=6.4;

(6)

2
5
5
7
=x:
3
14

5
7
x=
2
5
×
3
14

5
7
x÷
5
7
=
3
35
÷
5
7

x=

3
25

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