1 .7×(3+x)- 12=5x+88

Solution: 2 1+7x- 12=5x+88.

2x=79

x=79/2

2 .6.90÷x-90÷3x=3

Solution: 6.9-30 = 3 times

x=-7.7

3 .2.4÷5x-2.4÷6x= 1.6

Solution: 2.4 ÷ 5-2.4 ÷ 6 =1.6x.

x=0.05

4 .(9.7+2x)÷2=(5.5+5x)÷3

Solution: 29.1+6x =11+10x.

x=4.525

Second, solve the application problems by column equations.

1. In two fertilizer warehouses, the fertilizer in warehouse A is 2.4 times that in warehouse B, and the fertilizer in warehouse B is 44.8 tons less than that in warehouse A.. How many tons of chemical fertilizer are stored in warehouse A and warehouse B respectively?

Solution: Set up a warehouse to store X tons of chemical fertilizer.

x-x/2.4=44.8

x=76.8

Fertilizer stored in warehouse B: 76.8 ÷ 2.4 = 32 tons.

2. The goods in warehouse A are 560 tons more than those in warehouse B. If two warehouses carry 9 tons of goods at the same time, the remaining goods in warehouse A are three times that in warehouse B. How many tons of goods were there in warehouse A and warehouse B?

Answer: there are x tons of goods in warehouse a.

(x-9)÷(x-560-9)=3

x=822

Warehouse B was originally in stock: 822-560 = 262 tons.

The deposits of Party A and Party B are equal. Later, A took out 400 yuan and B deposited it in 300 yuan. At this time, B's deposit is three times that of A. How much did they have?

Suppose a had a deposit of x yuan.

x+300=3(x-400)

x=750

Both of them had their own savings, 750 yuan.

There are two counters in the video store. There are fewer tapes in counter A than in counter B. 120 ... If two counters each sell 164 boxes, the remaining amount of counter B is three times that of counter A. How many tapes are there in each of the two counters?

Solution: There used to be a tape X box at the armor counter.

x+ 120- 164 = 3(x- 164)

x=224

B There is adhesive tape at the counter: 224+ 120 = 344 boxes.

5. The school bought three sets of desks and chairs ***690 yuan, 1 A desk is more expensive than a chair, 80 yuan. How much is a table and a chair?

Solution: Suppose each table costs X yuan.

3×(x+x-80)=690

x= 155

Each chair: 155-80 = 75 yuan.

6. The average selling price of the three vegetables is around 0.8 yuan. It is known that class A vegetables are more expensive than class B vegetables per kilogram, 0.4 yuan. C food is 0. 1 yuan cheaper. What's the price of these three vegetables per kilogram?

Solution: Let's assume that the price of a vegetable is X yuan/kg.

(x+x-0.4+x+0. 1)= 3 = 0.8

x=0.9

Vegetable B price: 0.9-0.4 = 0.5 yuan/kg.

Third dish price: 0.9+0. 1 = 1 yuan/Jin.