To build a 240 km long highway, one eighth of the total length is built in the first week, and one sixth of the total length is built in the second week

240 × (1 / 6 - 1 / 8) indicates the number of kilometers repaired in the first week more than in the second week

Seventh grade math newspaper questions
There are 50 students in a class. In an activity, they are divided into four groups. The first group has (3a + 4B + x) students. The second group has six more than half of the first group. The third group has three more than one third of the sum of the first two groups
Expression)
2. It is known that the power of a = 3x is the power of XY + y, and the power of B = 2x is the power of 3xy-2y, where x and y satisfy the power of 2 (x-1 / 2) + Y-1 = 0 to find 3b-24

Well, it's a wrong number. It should be 3b-2a. How much should it be?

All the answers to the seventh grade mathematics PEP newspaper

Oh, all of them, do you want to give up high-voltage electricity? I didn't find the teacher or the post office! There are also students!

Mathematics newspaper

Level test a: 1-8bcaabc9, the answer is not unique; - 7 / 11a ^ BC 10,411, - 1.51220013,0.oo52614,4a ^ 2 + 7ab-15b ^ 215, n ^ 3-4n 16, [2n] ^ 2-117, & lt;! & gt;, - 3x-7 & lt; 2 & gt;, 7 / 8y XZ & lt; 3 & gt;, 2Ab 18,119, because the coefficients of the terms containing the letter X are all 0, the value of A-B + C has nothing to do with the value of X
Level test; 1-8bcbabddc 9, x ^ 2Y 10,0 11, a ^ 15 12, & gt;

The idiom "Bi" means "Mao"

There are no such idioms as () Bi () Mao. The idioms of ABCD D for Mao are all in the following: cherish feathers: it refers to people's reputation. It refers to cherishing one's reputation and acting very cautiously. Never catch Er Mao: catch, catch. Er Mao: white fingers, extended to the people of the last year. Don't catch the old people

21 28 33 42 43 60 () find the rule, what to fill in the brackets? This number is less than 100

45
Subtracting two adjacent digits
21 28 33 42 43 60 （）
7 5 9 1 17 （）
-2 4 -8 16
That is to say, the last line is all multiplied by - 2, - 2 multiplied by - 2 = 4, 4 multiplied by - 2 = 8, and so on. After 16, it should be - 32, so the last line is
-15, so it's 45

2x+25=4-5x

2x+5x=4-25
7x=-21
x=-3

This is a very interesting fairy tale book

Why can't a cat die when it falls down in the sky

It's hard for a cat to fall to death from a height. Because there are meat pads on its feet, and when it falls in the air, it can adjust its body balance in a second. It's also said that cats have a self-healing mechanism
P. S. cat's self-healing mechanism: during rest, the throat often makes a snoring sound. Some people think that this is a cat snoring, but American scientists have found that this is one of the ways of cat self-healing. The reason why people say that cats have nine lives is closely related to cat snoring during rest
Scientists have pointed out that both domestic cats and wild cats will snore after being injured. This kind of snoring from the laryngeal hair can help them cure bone and organ injuries, and also make them stronger. Scientists have also found from human experiments that exposing the human body to sound waves like a cat can help improve human bone
Scientists from the North Carolina Institute of zoological communication have found that the beating frequency of domestic cats is about 27 to 44 decibels, while that of pumas, South Central leopards, African Bobcats, cheetahs and South West Asian Wildcats is 20 to 50 decibels. This finding proves that the theory that human exposure to 20 to 50 Hz sound waves can enhance bone and promote bone growth is correct
Mackinsonal, director of the North Carolina Institute of zoological communication, said that because cats can use their own sound waves to heal their wounds, the legend of "nine life strange cats" is not absurd. Scientists pointed out that a certain frequency of sound waves can stimulate the treatment of bone injuries in cats, Its healing effect is just like that of human being exposed to ultrasound
Makinsenar said the discovery helped solve the mystery of "nine lives cat". She said the next step for scientists is to understand the healing process of purr in cats. All cats purr, and tigers are one of the few cats that don't purr
A recent study published in the Journal of the American Animal Medical Association pointed out that after investigating 132 cases of cats falling from an average height of six stories, 90% of them survived. Among them, one cat still survived falling from a 45 story building
In fact, if the height exceeds a certain limit, the cat will also fall to death

How to calculate 8 out of 17 △ 9 + 1 out of 9 × 8 out of 17

8 / 17 △ 9 + 1 / 9 × 8 / 17
=8/17×1/9+1/9×8/17
=8/17×（1/9+1/9）
=8/17×2/9
=16/153

To build a 240 km long highway, one eighth of the total length is built in the first week, and one sixth of the total length is built in the second week