Use 2,2,6,7 to calculate 24 points, use 2,4,10,10 to calculate 24 points, use 4,4,10,10 to calculate 24 points, use 5,5,5,1 to calculate 24 points Any answer is OK, as long as there is a correct answer~

Use 2,2,6,7 to calculate 24 points, use 2,4,10,10 to calculate 24 points, use 4,4,10,10 to calculate 24 points, use 5,5,5,1 to calculate 24 points Any answer is OK, as long as there is a correct answer~

2 2 6 7 :6+2*(2+7)
2 4 10 10 :(4/10+2)*10
4 4 10 10 :(10*10-4)/4
5,5,5,1:(5-(1/5))×5

Y = LNX function
How to draw the curve of y = LNX?

A: a C-shaped curve of the function image passing through the point (1,0) runs through the first and fourth quadrants. The curve of the fourth quadrant is gradually close to the Y axis, but does not intersect. The curve of the first quadrant is gradually away from the X axis

The volume of the hydrogen balloon is 4.5m3, the shell mass is 4kg, the air density is 1.29kg/m3, and the hydrogen balloon can hang multiple objects at most

The density of hydrogen is 0.0899kg/m3
According to the buoyancy formula, the buoyancy of the hydrogen balloon is f = p air * g * V = 56.889n. The weight of the hydrogen balloon is m = P hydrogen * V + m shell = 4.40455kg. Therefore, the mass of the hanging object is m = f / G-M = 1.40045kg

Surface area formula of triangular pyramid and prism

If point P moves on the curve y = x & # 179; - 3x & # 178; + (3 - √ 3) x + 3 / 4, and the inclination angle of the tangent passing through point P is α, then the value range of angle α is

y'=3x²-6x+3-√3
=3(x-1)²-√3≥-√3
So, α ∈ [0, π / 2) u [2, π / 3, π]

Do you have a standard mix proportion for C10 C15 C20 C25 C30 concrete? What about C15 plain concrete cushion? For example, how much cement, sand and gravel are needed for 20 cubic meters of C30 concrete?

I can tell you for sure, No. There are many reasons for different strength of concrete, such as different amount of constituent materials in concrete, different CBR value of aggregate, etc

6X + 3 (2x-3) = 6 - (x + 2) to solve the equation

6x+6x-9=6-x-2
6x+6x+x=9+6-2
13x=13
x=1

1 mol of any substance contains about 6.02 times 10 of 23 atoms. Is that right? Why?

No
1 mol of any substance contains about 6.02 times 10 of 23 particles
For example, 1 mol O2 contains about 6.02 times 10 of 23 oxygen molecules, because oxygen particles are oxygen molecules
1molc contains about 6.02 times 10 of 23 carbon atoms, because the carbon particles are carbon atoms

Relationship between volume and mass density
If three identical cups are filled with water and iron, aluminum and copper of equal mass are completely immersed in water, what is the largest volume of water?
A. B. for iron, C. for aluminum, D. for copper
What is the correct answer? What is the reason?

B
The same mass of metal is the largest volume of aluminum block, because the density of aluminum is the smallest, so B

2.7 times the square of 1.8 minus 1.2 times the square of 1.2

2.7 times the square of 1.8 minus 1.2 times the square of 1.2
=2.7*3.24-1.728
=7.02