② 0.52a+2b

2: 0.5 6 4

164 7/ 18 7

3. Not set ...

5x - 4=56

5x=56+4

x= 12

4. Not set ...

﹙ 120+95﹚x= 1262

2 15x= 1262

x≈6

5. Solution: The storage capacity of Xiaolangdi Reservoir on the Yellow River is x cubic meters, while that of Three Gorges is 3x.

3x - x=260

2x=260

x= 130

6:

One piece 18 23.5 25

b 26 37 40

7. Solution: ...

x×﹙ 1- 10%﹚= 14.4

0.9x= 14.4

x= 16

8. Solution: ...

40%x+50%x= 120

0.9x= 108

x= 120

9: ① Figure 1 a+ 1 a+2 a+3

Figure 2 a+7 a+8 a+9

Figure III a+ 1

a+7 a+8

The one behind the horizontal row is 1 more than the last one, and the one below the vertical row is 7 more than the last one.

② Omission