1.x( 1+ 18%)= 17

2. let the annual interest rate be x.

25000( 1+x)？ =27200

∴x=4.3 1%

A: The annual interest rate is 4.3 1%.

3. Assuming that the output of the first field was xkg last year, the output of the second field was (470-x)kg.

∴x( 1+ 16%)+(470-x)( 1+ 10%)=523

∴x= 100

Answer: The first output is 100kg, and the second output is 370kg.

Suppose last year's expenditure was X yuan, then the income was (12000+x) yuan.

( 12000+x)( 1+20%)-x( 1- 10%)= 23400

∴x=30000

( 12000+x)( 1+20%)= 50400

x( 1- 10%)=27000

A: The income this year is 50,400 yuan, and the expenditure is 27,000 yuan.

5. The old school building of x square meters will be demolished.

20000-x+3x+ 1000 = 20000( 1+20%)

∴x= 1500

Demolition area = 1500m2

New area = 3x+ 1000 = 5500m2.

Cost = 80×1500+700× 5500 = 3970000 yuan.

A: Demolition of old school buildings 1500 square meters. It will cost 3.97 million yuan to complete this plan.

6.

(1) 1 month =18 ÷ (1+20%) =1.5 million yuan.

(2) February =15.12× (1+10%) =166.32 million yuan.

65438+ 10 month =16.632÷ (1+20%) =138600 yuan.

(3) Let the turnover in February be X million yuan.

∴x÷( 1+20%)+x+x×( 1- 10%)=52.48

∴x= 19.2

∴ 1 month = 65438+600,000 yuan

February = 192000 yuan

March = 172800 yuan

After your hard work, I hope it will help you and adopt it. Thank you ~