The solution set of inequality | x-4 | + | 3-x | < 2 is______ ．

The solution set of inequality | x-4 | + | 3-x | < 2 is______ ．

From the meaning of absolute value, | x-4 | + | 3-x | is the sum of the distances from the corresponding points of X on the number axis to the corresponding points of 4 and 3, and its minimum value is equal to 1. While the sum of the distances from the corresponding points of 2.5 and 4.5 on the number axis to the corresponding points of 4 and 3 is equal to 2, the solution set of the inequality | x-4 | + | 3-x | < 2 is (2.5, 4.5), so the answer is: (2.5, 4.5)

Inequality-5

-2

What is 6:40

40 minutes = 40 / 60 hours = 2 / 3 hours
6:40 = 6 right 2 / 3

A rectangular playground is 348 meters in circumference and 69 meters in width. How many square meters is its area?

The length of rectangle: 348 △ 2-69, = 174-69, = 105 (m), the area of playground: 105 × 69 = 7245 (M2); answer: the area of playground is 7245 m2

It is known that the circumference of triangle ABC is 56 cm, AB is 4 cm more than 3 times the length of AC side, AC is 5 cm more than half the length of BC side, how many cm are each of a, B and C?

AB+AC+BC=56
AB=3AC+4
AC=1/2BC+5 BC=2AC-10
3AC+4+AC+2AC-10=56
6AC=62
AC=31/3
AB=31/3×3+4=35
BC=62/3-10=32/3

The matching method of x square minus 2x minus 2 = 0

x^2-2x-2=0
x^2-2x+1-1-2=0
(x-1)^2=3
X = 1 + G radical 3
or
X = 1-radical 3
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What kind of pollution will the glass curtain walls of high-rise buildings cause
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Light pollution, class sometimes listen carefully is very important

Small production of science and technology suitable for grade five of primary school
But it must be novel. It must not be too difficult

1. Homemade badminton
Preparation materials: one empty drink bottle, two mesh fruit foam mesh, one rubber band and one glass marble.
1. Take a 250 ml empty beverage bottle and cut off the upper part of the bottle;
2. Divide the cut parts into 8 parts, cut them to the bottleneck with scissors, and then cut each part into petal shape with the same size;
3., the bubble fruit net is sleeved outside the bottle body, and the rubber band is fixed on the bottle mouth.
4. wrap another glass of fruit net in a glass marble, squeeze it into the bottle mouth, lay tight and expose about 1 centimeters.
5. Cut off half of the table tennis ball, cover the bottom of the hemisphere on the bottle mouth, cut the four sides into whiskers, cover the bottle mouth and fix it with a rubber band
6. After beautification, a homemade badminton is finished. Play with a badminton racket to see how the effect is?
2. Homemade Soap paper
Manufacturing materials and tools:
White paper with good hygroscopicity, small soap, a brush and disposable beverage can
Production method:
First, cut the soap into pieces and put it in a jar. Then put the cup on the stove and heat it. When the soap melts, cut the white paper into matchbox size, coat it with soap one by one, and then take it out and dry it in the shade
3. Homemade hot air balloon
1. First, we use soft paper to cut 6-8 leaves
2. Fold them in half and glue their sides together to make a balloon
3. Glue the four wires to the bottom of the balloon with adhesive tape. Fix the other end of the wires on the table with rubber paste
4. Adjust the speed of the hair dryer as slowly as possible. Align the air dryer mouth up to the bottom opening and turn on the switch. The balloon will slowly grow larger, tighten the thin line and leave the table
4. Homemade flashlight
The specific manufacturing method is as follows: take off one cover of a waste can (such as Lulu beverage can) and dent the other end with a round hammer. Roll up two No. 1 batteries with thick corrugated cardboard, and put the positive pole and negative pole of the batteries into the can with upward and downward. Find a suitable plastic cover (such as the magic big roll box cover can be buckled on Lulu beverage can), and dig a small round hole in the center of the box cover, The size of the hole should be such that the bulb can be inserted tightly. Insert the bulb base into the small hole. Take a piece of tracing wire and peel off the wire at both ends. One end is wound on the lamp holder, and the other end is pierced through a small hole on the side of the plastic cover. Cover the plastic cover on the can. Check whether the bulb and battery are tightly contacted. Here, the disposable flashlight is ready, Use your thumb to press the wire from the side wall on the unpainted weld of the can, and the flashlight will light up. If you jump off the wire with your thumb, the flashlight will go out. It is very convenient to use
5. Homemade solar cooker
Find a concave reflector bowl on a large flashlight, and use a rigid foam or wood to cut a cylinder about 4 centimeters in diameter, so that the diameter can be tightly inserted into the round hole of the reflecting bowl. A hole is drilled horizontally on one end of the cylinder and penetrated into a wire with diameter equal to the diameter of the hole. Then the two ends of the iron wire outside the cylinder are folded to 90 degrees. Leave 5 centimeters in each piece. Insert the column into the round hole of the reflecting bowl, then insert the two ends of the wire on a foam plastic or wooden floor. Sharpen the two ends of a fine bamboo stick, insert one head into the center of the reflecting bowl, and insert a small piece of potato at the other end. Put the device in the sun, let the reflecting bowl move towards the sun, and then adjust the length of the bamboo stick patiently. Let the potato just be in the focus of the light. Before long, the potato will be baked by the sun and smell
6. Homemade colored candle
Materials: colored crayons, wax
Production method:
1. Find an abandoned canned beverage bucket (such as a 1.25 liter coke bottle), trim off the lid and cut the wax into the bucket
2. Put the bucket into hot water, and stir the wax in it to make it melt completely. It's better to use boiling water. But please ask your parents for help or carry out this step under their supervision
3. Pour the melted liquid into a well-shaped container (such as the heart-shaped frame of a small piece of erqiaokenai). Don't pour too much. As for the reason, look down. Of course, you need to put the thread for candle wick in the container first
4. When the original wax cools down, ah pours the melted colored crayon liquid into it according to the method of Pu Mian (colored crayons are in use at this time). In this way, wax of different colors is added layer by layer, and a beautiful candle is made
7. Self made wall hanging flower basket
Materials and tools: two sprite drink bottles, glue, knife, scissors
Production method:
1. Take off the green bottom cover of a sprite drink bottle, cut it into lotus shape, turn it down and stick it with the bottle body to form a base
2. Cut a 2 cm wide green ring on the green bottom cover and put it on the bottle
3. Remove the bottle neck and cut out a wide strip of 13cm long and 8cm wide and several narrow strips of 3cm wide
4. Use a cutter to carve patterns on 3cm narrow strips, as shown in Fig. 3, and then turn these narrow strips outward and insert them into the green ring from bottom to top
5. Take another drink bottle and use the bottle body to cut out 6 capsules 17 cm long with scissors
6. Nail the flower basket on the wall, insert the leaves and flowers, and the wall hanging flower basket is made
8. Self made cockroach catching box
Take a piece of 220 × 150 (mm) cardboard
The most important part of the capture box is the capture surface. Take a piece of plastic film, cut it to the same size as the bottom of the box, and spread it on the bottom of the box with adhesive. The key to whether a cockroach can be caught is the adhesive. The adhesive has two functions: one is to introduce the cockroach into the box, the other is to stick it firmly on the capture surface. The preparation of attractant: mix 40% meat powder, 50% flour and 10% bean cake, the total amount is about 20g, Mix 20 grams of rosin and 10 grams of vegetable oil, heat them to gelatinous state, mix attractant and adhesive evenly, and then make adhesive
Apply the adjusted paste evenly on the catching surface lined with plastic film, fold inward according to the original dotted line, and finally insert the tongue piece B into the notch a
Because the mixture of rosin and vegetable oil is not dry, it can make the bait sticky for as long as a week. Put the trap box in the place where cockroaches appear. Because the box is dark and has the bait that cockroaches like, cockroaches will climb into the box to fight for bait and stick it on it. When the box is full, the box can be flattened and discarded, and the plastic film can be removed to replace the plastic film coated with bait, so that the box can be used again
If the size of the catching box is enlarged and the composition of the adhesive is slightly adjusted, the paper rat catching can be made by thickening the coating

Given x ^ 2-5x + 1 = 0, find the value of (1) x ^ 2 + x ^ 2 / 1; (2) x ^ 4 + x ^ 4 / 1

(1) Because x ^ 2-5x + 1 = 0, then x + 1 / x = 5 and x ^ 2 + 1 / x ^ 2 = (x + 1 / x) ^ 2-2, so x ^ 2 + 1 / x ^ 2 = (x + 1 / x) ^ 2-2 = 5x5-2 = 23 (2) because x ^ 2 + 1 / x ^ 2 = 23 (from above) and x ^ 4 + x ^ 1 / x ^ 2 = (x ^ 2 + 1 / x ^ 2) ^ 2-2, so x ^ 4 + x ^ 4 = (x ^ 2 + 1 / x ^ 2) ^ 2-2 = 23 ^ 2-2 = 529

According to the plan of the school basketball court, the length of the basketball court is 13 cm and the width is 7 cm. If the scale of the plan is 1:200, the actual area of the basketball court can be calculated
Come on, do it!

Let the actual length be x cm and the actual width be x cm. 2600 cm = 26 M
13: X = 1:200 7: x = 1:200 1400cm = 14m
X = 13x200 x = 200x7 actual basketball court area:
X = 2600 x = 1400 26x14 = 364 (M3)
A: the actual area of the basketball court is 364 cubic meters