A math problem in a hurry! Hurry, hurry, math problems!

Solution: 1/4 of the number of people in a class is 1/5 of the number of people in the second class 1 more, that is, the number of people in a class is 4 5 more than 4 people in the second class, 1/4 of the number of people in a class and 1/5 of the number of people in the second class is equal to 1/3 of the number of people in the third class, where 1/4 of the number of people in the first class is 1/5 more than 1/5 of the number of people in the second class, and the number of people in the first class is converted into the number of the second class, that is, the number of people in the third class is 6 5 more than 3 people in the second class, and the number of people in the second class is 4 5 + 4 people + the number of people in the second class + 6 5 + 3 people in the second class =37 people.

Then, the number of students in the second class is:

37-4-3) (4 5 + 1 + 6 5) = 10 (people) The number of people in a class is:

10*1 5+1) 1 4=12 (person).

The number of students in Class 3 is:

12*1 4+10*1 5) 1 3=15 (person).

a-b+2|The square of +(a-2b) = 0

Then a-b+2=0

a-2b=0

Solution: a=-4

b = -2 then (-2a) squared * b = 8 * 8 * (-2) = -128

Because |a-b+2|=a-2b=0

So a=2b(1).

Substituting (1) into a-b=-2 gives b=-2

Substituting b = -2 into (1) gives a = -4

So. a=-4

b=-2

a-b+2=0, so a-b=-2

a-2b)2=0, so a=2b

So b=-2 a=0

So get 0

a-b+2|The square of +(a-2b) = 0

a-b+2|>=0

The square of +(a-2b) = 0

A-b+2=0 and a-2b=0 are introduced

a=-4 b=-2

2a) squared *b = -128

(Just count it the other way around.)

It's the same with column equations.

Set body temperature x degrees Celsius.

It's the same with solution x.

Hope it helps.

Well?? The temperature at Celsius is 37 degrees, which is the normal temperature of the human body, so Xiaohong doesn't have a fever.

Fahrenheit.

Celsius = 5 (Fahrenheit -32) 9

Substituting calculations: the temperature is 37°C, and there is no fever.

The temperature in Celsius is 37 degrees, the normal temperature of the human body, no fever, just convert!

1) The trees planted by the first student are half of the total number of trees planted by other students, that is, the trees planted by the first student are the total number (1 2) (1+1 2)=1 3, the trees planted by the second student are one-third of the total number of trees planted by other students, that is, the trees planted by the first student are the total number of trees planted by the first student (1 3) (1+1 3)=1 4, the trees planted by the third student are a quarter of the total number of trees planted by other students, and the trees planted by the first student are the total number of trees (1 4) (1+1 4) = 1 5, and the fourth student is 1-1 3 -1 4 -1 5=The total of 13 60 is 13 (13 60) = 60

2) B's completion of 10 days of work is equivalent to 12-4=8 days for B, 12-4=8 days for A, and B's work efficiency is 8 2=4 times that of A.

Team A does it alone 12+12*4=60 days.

3) B: 9-8 = 1 day of work, which is equivalent to 8-6 = 2 days of work of A, and B does 8 2 + 8 = 12 days alone.

Four students planted trees, the first student planted half of the total number of trees planted by other students, the second student planted one-third of the total number of trees planted by other students, the third student planted a quarter of the total number of trees planted by other students, and the fourth student planted exactly 13 trees. Q: How many trees did the four students plant?

The ratio of the trees planted by the first student to the total number = 1 2 (1+1 1 2) = 1 3, the ratio of the trees planted by the second student to the total number = 1 3 (1 + 1 3) = 1 4 The ratio of the trees planted by the third student to the total number = 1 4 (1 + 1 4) = 1 5 The four students planted trees together = 13 (1-1 3-1 4-1 5) = 60 trees do not need the equation of one yuan and one time, it is better to use arithmetic, if it is good, give more points! Question added:

One more more! ~~

If a project can be completed in 12 days by teams A and B, if teams A and B work together for 4 days first, and team B completes the rest in 10 days, then how many days can team A complete the project alone?

1 =120 days.

If A and B do it alone for 6 days, and then B can complete the task in 9 days, how many days does it take for B to complete the project alone?

1 = 12 days.

Your question is wrong, 1 2 + 1 3 + 1 4 = 7 6 7 6 1, the number of trees planted by the first three students is greater than the total number, so this question is wrong is wrong.

Attached: (1) 1 12 4 10 = 1 30

1 (1 20) = 20 (days).

A: Team A can complete the project in 20 days alone.

1 (1 12) = 12 (days).

A: The team can complete the project in 12 days alone.

Let the total cost be in units of 1

Then the unit price of the desk is 1 20, the chair is 1 30, then 1 set is 5 60 = 1 12

1 divided by 1 12 is 12 sets.

It's easier to understand.

If you donate x yuan, then a desk x 20 yuan, a chair x 30 yuan, add up to get a set of desks and chairs x 12 yuan, x (x 12) = 12

So you can buy exactly 12 sets.

The pear tree accounts for 4/5 and the peach tree accounts for 1/5, and the sum is 5/5, which is 1, so there are only these two trees in the orchard.

You can divide 1800 by 4/5 to get the total number of fruit trees, 2250, and multiply by 1/5 to get 450 peach trees

You can also divide a simple 1800 by 4 to get a peach tree of 450. This is very easy to understand, the pear tree accounts for 4 parts, and the peach tree accounts for 1 part, so the amount of pear tree divided by 4 parts to get one part is the amount of one part of the peach tree.

The orchard has 1800 pear trees, which accounts for 4/5 of the total number of fruit trees, so the orchard has a total of trees (1800 4/5) = 2250 trees.

Peach trees: 2250*1 5=450 trees.

How many peach trees: 1800 times 1/5 = 360 (trees).

Solution: First find the total number of fruit trees 1800 4 5 = 2250 (trees) and then find the peach trees 2250 1 5 = 450 (trees).

Column composite formula: 1800 4 5 1 5 =450 (tree) answer; 450 peach trees?