4、B 5、C 6、B

Second, 1,? 2、? 3、? 14、? 5、?

Three. 1，90-b

2、2a + 15

3、 1.5x 2.5x

4, 5 years

5、C A B D

How much are 20 carnations and Y roses?

7, 4 meters (m+b) meters

8. 1000 meters+10 cattle

Four. x = 192 y = 250 b = 50 m = 6.8

5. (1) Money for 4 coats = 146 yuan 4y = 146.

(2) distance traveled+distance not traveled = 800m x+ 150 = 800.

(3) Paid currency-payable currency = returned currency 50-a = 15

(4) Who sits at each table? Number of tables-138 people 6n = 138

(5) Number of two buses +4 people = 20 people 2x+4 = 20

6. m-2.15x =103y = 7.5x = 9.6.

7. 1, solution: suppose there are x chickens. 3 16-x = 42，x = 274。

2. solution: let the new star team win x games. We get 3x+2 = 4 1 and x = 13.

3. solution: let the length be x cm. (20 + x)？ 2 = 1 10，x = 35。

4. Solution: Suppose the gray rabbit moves X. 32-6 = 48 and x = 18.

Intelligent gas station

Solution: Suppose there are X rabbits and (12-x) chickens. 4x + 2( 12 - x) = 38，

Find x-7. 12-7 = 5 (only), so there are 5 chickens and 7 rabbits.