? One-dimensional linear equation:

1。 7(2x- 1)-3(4x- 1)= 4(3x+2)- 1；

2.。 (5y+ 1)+( 1-y)=(9y+ 1)+( 1-3y)；

3。 20%+( 1-20%)(320-x)= 320×40%

4。 2(x-2)+2=x+ 1

5。 2(x-2)-3(4x- 1)= 9( 1-x)

6。 x/3 -5 = (5-x)/2

7。 2(x+ 1)/3 = 5(x+ 1)/6- 1

8。 ( 1/5)x+ 1 =(2x+ 1)/4

9。 (5-2)/2 - (4+x)/3 = 1

10。 x/3 - 1 = ( 1-x)/2

1 1。 (x-2)/2 - (3x-2)/4 =- 1

12。 1 1x+64-2x = 100-9x

13。 15-(8-5x)=7x+(4-3x)

14。 3(x-7)-2[9-4(2-x)]=22

15。 3/2[2/3( 1/4x- 1)-2]-x = 2

16。 2(x-2)-3(4x- 1)= 9( 1-x)

17。 1 1x+64-2x = 100-9x

18。 15-(8-5x)=7x+(4-3x)

19。 3(x-7)-2[9-4(2-x)]=22

20。 3/2[2/3( 1/4x- 1)-2]-x = 2

2 1。 2(x-2)+2=x+ 1

1。 7(2x- 1)-3(4x- 1)= 4(3x+2)- 1

2。 (5y+ 1)+( 1-y)=(9y+ 1)+( 1-3y)

3。 [ (- 2)-4 ]=x+2

4。 20%+( 1-20%)(320-x)= 320×40%

5。 2(x-2)+2=x+ 1

6。 2(x-2)-3(4x- 1)= 9( 1-x)

7。 1 1x+64-2x = 100-9x

8。 15-(8-5x)=7x+(4-3x)

9。 3(x-7)-2[9-4(2-x)]=22

10。 3/2[2/3( 1/4x- 1)-2]-x = 2

1 1。 5x+ 1-2x=3x-2

12。 3y-4=2y+ 1

13。 87X* 13=5

14。 7Z/93=4 1

15。 15X+863-65X=54

16。 58Y*55=27489

17。 2(x+2)+4=9

18。 2(x+4)= 10

19。 3(x-5)= 18

20。 4x+8=2(x- 1)

2 1。 3(x+3)=9+x

22。 6(x/2+ 1)= 12

23。 9(x+6)=63

24。 2+x=2(x- 1/2)

25。 8x+3( 1-x)=-2

26。 7+x-2(x- 1)= 1

27。 x/3 -5 = (5-x)/2

28。 2(x+ 1)/3 = 5(x+ 1)/6- 1

29。 ( 1/5)x+ 1 =(2x+ 1)/4

30。 (5-2)/2 - (4+x)/3 = 1

15x-8(5x+ 1.5)= 18 * 1.25+x

3X+ 189=52 1

4Y+ 1 19=22

3X* 189=5

8Z/6=458

3X+77=59

4Y-6985=8 1

87X* 13=5

7Z/93=4 1

15X+863-65X=54

58Y*55=27489

1.？ 2(x-2)-3(4x- 1)= 9( 1-x)

2.？ 1 1x+64-2x = 100-9x

3.？ 15-(8-5x)=7x+(4-3x)

4.？ 3(x-7)-2[9-4(2-x)]=22

5.？ 3/2[2/3( 1/4x- 1)-2]-x = 2

6.？ 2(x-2)+2=x+ 1

7.？ 0.4(x-0.2)+ 1.5=0.7x-0.38？

8.？ 30x- 10( 10-x)= 100？

9.？ 4(x+2)=5(x-2)

10.？ 120-4(x+5)=25

1 1.？ 15x+863-65x=54

12.？ 12.3(x-2)+ 1 = x-(2x- 1)

13.？ 1 1x+64-2x = 100-9x

14.？ 14.59+x-25.3 1=0

15.？ x-48.32+78.5 1=80

16.？ 820- 16x=45.5×8

17.？ (x-6)×7=2x

18.？ 3x+x= 18

19.？ 0.8+3.2=7.2 ?

20.？ 12.5-3x=6.5

2 1.？ 1.2(x-0.64)=0.54

22.？ x+ 12.5=3.5x

23.？ 8x-22.8= 1.2

24.？ 1\ 50x+ 10=60

25.？ 2\ 60x-30=20

26.？ 3\ 3^20x+50= 1 10

27.？ 4\ 2x=5x-3

28.？ 5\ 90= 10+x

29.？ 6\ 90+20x=30

30.？ 7\ 69 1+3x=700

1 ? 2x- 10.3x= 15

2 ? 0.52x-( 1-0.52)x=80

3 ? x/2+3x/2=7

4 ? 3x+7=32-2x

5 ? 3x+5( 138-x)=540

6 ? 3x-7(x- 1)=3-2(x+3)

7 ? 18x+3x-3 = 18-2(2x- 1)

8 ? 3(20-y)=6y-4(y- 1 1)

9 ? -(x/4- 1)=5

10 ? 3[4(5y- 1)-8]=6

application problem

1. Input a batch of latest industrial dynamic information into the management storage network. Party A does it alone for 6 hours, Party B does it alone for 4 hours, Party A does it for 30 minutes first, and then Party A and Party B do it together. How many hours does it take for Party A and Party B to finish this work together?

Solution: It takes X hours for Party A and Party B to complete the work together.

According to the meaning, x+(+) x = 1.

Solve this equation and get x=

=2 hours 12 minutes

A: It will take two hours for Party A and Party B to complete this work together.

2. The two brothers are 15 and 9 years old respectively this year. How many years later, my brother is twice as old as my brother?

Solution: Suppose that after X years, my brother is twice as old as my brother.

X years later, the elder brother's age is 15+x, and the younger brother's age is 9+X.

2×(9+x)= 15+x From the meaning of the question.

18+2x= 15+x，2x-x= 15- 18

∴x=-3

Three years ago, my brother was twice as old as my brother.

3. Pour the water in a cuboid iron box filled with water into a cylindrical bucket with an inner diameter of 200mm. The length, width and height of the water in the iron box are 300mm, 300mm and 80mm respectively. Just fill it up and find the height of the cylindrical bucket (accurate to 0. 1mm, ≈ 3. 14).

Solution: let the height of the cylindrical bucket be x mm, according to the meaning of the question.

? & amp#8226; ()2x=300×300×80

X is about 229.3

Answer: The height of the cylindrical bucket is about 229.3 mm. 。

A train must cross the first and second iron bridges at a speed of 600 meters per minute. It takes 5 seconds longer to cross the second iron bridge than the first one, and knowing that the length of the second iron bridge is 50 meters shorter than that of the first one, try to find the length of each iron bridge.

Solution: If the length of the first iron bridge is x meters, the length of the second iron bridge is (2x-50) meters, and the time required to cross the first iron bridge is minutes.

It takes several minutes to cross the second railway bridge. According to the meaning of the question, can the equation be listed + =

Solve the equation x+50=2x-50 to get X =100 ∴ 2x-50 = 2×100-50 =150.

Answer: The length of the first railway bridge is 100 meters, and the length of the second railway bridge is 150 meters.

5. There is a 50g tricolor ice cream, and the proportion of brown, red and white ingredients is 2: 3: 5. How many grams of brown, red and white ingredients does this tricolor ice cream have?

Solution: Make the brown content in this tri-color ice cream 2x grams.

Then the red and white components are 3xg and 5x g, respectively. According to the question, 2x+3x+5x=50.

Solve this equation and get x=5? So 2x= 10, 3x= 15, 5x=25.

A: The ingredients of this tri-color ice cream are 10g, 15g and 25g respectively.

6. There are 16 workers in a workshop, and each person can process 5 parts A or 4 parts B every day. Of these 16 workers, some process parts A and the rest process parts B. It is known that each part A can make a profit 16 yuan, and each part B can make a profit in 24 yuan. If this workshop makes money,

Solution: Suppose that there are X workers processing Part A on this day.

Then five type A parts and four type B parts were processed on this day (16-x). According to the meaning of the question, it is16× 5x+24× 4 (16-x) =1440.

X=6 A: There are 6 workers processing Class A parts on this day.

7. The basic price of domestic electricity for residents in a certain area is 0.40 yuan per kWh. If the monthly electricity consumption exceeds one kWh, the excess will be charged at 70% of the basic electricity price.

(1) a household used 84 kwh of electricity in August, and * * * paid 30.72 yuan for electricity, so it was a.

(2) If the average electricity bill of users in September is 0.36 yuan, how many kilowatts of electricity will be used in September? How much should I pay for the electricity?

Solution: (1) From the meaning of the question, we get 0.4a+(84-a)×0.40×70%=30.72, and a=60.

(2) If the electricity consumption in September is X kWh, then 0.40×60+(x-60)×0.40×70%=0.36x is x=90.

So 0.36×90=32.40 (yuan) A: In September, * * * used 90 kwh of electricity, and the electricity bill should be 32.40 yuan.

8. An appliance store plans to buy 50 TV sets from manufacturers for 90,000 yuan. It is known that this manufacturer produces three different models of TV sets, with ex-factory prices of A 1.500 yuan, B 2 1.000 Yuan and C 2500 Yuan respectively.

(1) If the appliance store buys 50 sets of two different models of TV sets at the same time, which costs 90,000 yuan, please study the purchase scheme of the store.

(2) If a shopping mall sells a model A TV set with a profit of 150 yuan, a model B TV set with a profit of 200 yuan and a model C TV set with a profit of 250 yuan, and buys two different TV sets at the same time, which scheme is the most profitable?

Solution: according to the three schemes of buying a and b, b and c, a and c TVs,

If you buy X A-type TVs and Y B-type TVs.

(1)① When buying two kinds of TV sets, A and B, and B buys (50-x) sets, the equation can be obtained.

1500x+2100 (50-x) = 90000, which means 5x+7 (50-x) = 300x = 50x = 25 50-x = 25.

(2) When buying two kinds of TV sets, A and C, C will buy (50-x) sets.

The equation1500x+2500 (50-x) = 90003x+5 (50-x) =1800x = 3550-x =15 can be obtained.

③ When buying B and C TVs, the number of C TVs is (50-y), and the equation is 2 100y+2500(50-y)=90000.

2 1y+25(50-y)=900, 4y=350, irrelevant.

From this, we can choose two schemes: one is to buy 25 TV sets in A and B respectively; The second is to buy 35 A TV and 15 C TV.

(2) If scheme ① in (1) is selected, the profit can be150× 25+250×15 = 8750 yuan? If you choose scheme ② in (1), you can make a profit.

150× 35+250×15 = 9000 (yuan) 9000 & gt Therefore, in order to obtain the maximum profit, the second scheme is selected.

9. In the knowledge contest held in a certain district, the average score of a school team was 88, in which the average score of girls was higher than that of boys 10%, and that of boys was higher than that of girls 10%. What is the average score of boys and girls?

If the number of girls is x, the number of boys is1.1x.

If the average score of boys is a, the average score of girls is1.1a.

Finally, I wish you success in your studies!