问题 解答题
4+
2
5
x=22
x-0.2x=48
1
3
x-5=18
2
3
x+
1
2
x=84
20%x=220%X=16
X-60%X=2100+50%X=450χ-
1
4
χ=24.
答案

(1)4+

2
5
x=22,

4+

2
5
x-4=22-4,

2
5
5
2
=18×
5
2

x=45;

(2)x-0.2x=48,

0.8x=48,

0.8x÷0.8=48÷0.8,

x=60;

(3)

1
3
x-5=18,

1
3
x-5+5=18+5,

1
3
x×3=23×3,

x=69;

(4)

2
3
x+
1
2
x=84,

7
6
x=84,

7
6
6
7
=84×
6
7

x=72;

(5)20%x=2,

0.2x÷0.2=2÷0.2,

x=10;

(6)20%x=16,

0.2x÷0.2=16÷0.2,

x=80;

(7)x-60%x=2,

0.4x=2,

0.4x÷0.4=2÷0.4,

x=5;

(8)100+50%x=450,

100+0.5x-100=450-100,

0.5x÷0.5=350÷0.5,

x=700;

(9)x-

1
4
x=24,

3
4
x=24,

3
4
4
3
=24×
4
3

x=32.

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