Primary school fifth grade mathematics urgent! Please answer in detail, thank you! (4 21:2:33) Solve the following equation 6X+6x8=72 (X+8)x6=72 8(X-2.6)=32 8X-8x2.6=32 0.3x7+4X=12.5 1.6X-24x2=36

Primary school fifth grade mathematics urgent! Please answer in detail, thank you! (4 21:2:33) Solve the following equation 6X+6x8=72 (X+8)x6=72 8(X-2.6)=32 8X-8x2.6=32 0.3x7+4X=12.5 1.6X-24x2=36

6x=24
x=4
6x+48=72
x=4
8x-20.8=32
8x=52.8
x=6.6
equally
2.1+4x=12.5
4x=10.4
x=2.6
1.6x=48+36
1.6x=84
x=21/4

What is 24 divided by 0.2

24÷0.2=120
24÷0.2=240÷2=120

Time and application (11 21:53:19)
&#Uncle Wang drank a glass of beer. After half an hour, he added another 5 / 6 liter to the glass. This is 1 / 18 liter less than the original beer. How many liters was this beer?

The total amount of beer can be regarded as a unit
Uncle shewang drinks x liters per hour
X/2+5/6=1-1/18
The solution is x = 9 / 8 liter

Simple operation: 15.8 * 5.8 + 4.2 * 4.2 + 11.6 * 4.2

15.8*5.8+4.2*4.2+11.6*4.2=15.8*5.8+(4.2+11.6)*4.2=15.8*5.8+15.8*4.2=15.8*(5.8+4.2)=15.8*10=158

The school held a sports meeting. Xiaoming, Xiaogang and Xiaolong competed in the 100 meter walking race. When Xiaoming arrived at the finish line, Xiaogang was 2 meters away from the finish line, and Xiaolong was 5 meters away from the finish line. If the speed of the three did not change, how many meters was Xiaolong away from the finish line when Xiaogang arrived at the finish line? (two decimal places are reserved for the result)

100-100 × 100 − 5100 − 2 = 100-100 × 9598 ≈ 100-96.94 = 3.06 (m) a: when Xiaolong just arrived at the end, Xiaolong was 3.06 meters away from the end

Among the natural numbers from 1 to 1999, how many are multiples of 3 and multiples of 5?

The least common multiple of 3 and 5 is 3 * 5 = 15
1999 / 15 = 133 (more than 4)
So there are 133 natural numbers from 1 to 1999 that are multiples of 3 and multiples of 5

Use + - * / to make the number equal to 241.9 7 5 4 2.10 8 7 4 after operation

（1.9+ 7+ 5+ 4+ 2.10）×（ 8- 7）+ 4=24

A cuboid water tank without cover is welded with a rectangular iron sheet 120 cm long and 40 cm wide

According to what you mean. Let's set the four corners of the rectangular iron sheet to delete a square, so as to maximize the volume and just enclose an open water tank. Let's set it as X, then the formula is (120-2x) * (40-2x) * x is to find the maximum value of this, which is equal to the mathematical formula

A school library is equipped with one table, six chairs, two tables, 10 chairs, three tables and 14 chairs. When n + 1 tables are placed, more chairs should be placed

Let n be a table, when n = 1, the number of chairs is 6; when n = 2, the number of chairs is 6 + 4; when n = 3, the number of chairs is 6 + 4 + 4~~~~~~~
It can be concluded that N changes, and the number of chairs changes by 6 + 4 (n-1)
So we get: 6 + 4 (n-1)

How many square decimeters is one meter equal to

One square meter is equal to 100 square decimeters