2. 2, 7, 10 are 24, 5, 13, 6, 7

2. 2, 7, 10 are 24, 5, 13, 6, 7

2 × (7 + 10 ÷ 2)=24
6*7-13-5=24

Find the volume of the solid formed by the figure surrounded by the parabola y ^ 2 = 2x and the straight line x = 1 / 2 rotating around the straight line y = - 1

The part of the parabola above the x-axis is y = √ (2x), and the part below the x-axis is y = - √ (2x)
Straight line x = 1 / 2 and parabola intersect at a (1 / 2, - 1)
At x (0 < x < 1 / 2): the rotator is a ring whose inner diameter is r = - √ (2x) - (- 1) = 1 - √ (2x)
Outer diameter r = √ (2x) - (- 1) = 1 + √ (2x)
Sectional area s = π R & # 178; - π R & # 178; = 4 π √ (2x)
The volume is the integral of s from 0 to 1 / 2, and the result is 4 π / 3

55 cubic decimeter = () cubic meter

1 cubic meter = 1 000 cubic decimeter
1 cubic decimeter = 0.001 cubic meter
therefore
55 cubic decimeter = 0.055 cubic meter

It is known that the top view of a geometry is a square with side length 2 as shown in the figure, and the front view and the left view are regular triangles with side length 2, then the total area is ()
A. 8B. 12C. 4(1+3)D. 43

Because the geometry is a pyramid, the height of the side triangle is 2, the bottom is a square with side length 2, and the surface area of the geometry is 4 × 12 × 2 × 2 + 2 × 2 = 12

If the parabola y = x2 + BX + C is translated 2 units to the left and 3 units to the upper, the parabola y = x2-2x + 1 is obtained, then the values of B and C are ()
A. b=2，c=-2B. b=-6，c=6C. b=-8，c=14D. b=-8，c=18

Y = x2-2x + 1 = (x-1) 2, translate 2 units to the right, then translate 3 units to the down, y = (x-1-2) 2-3 = x2-6x + 6. So B = - 6, C = 6. So B

How many cubic meters is a ton of sand

Due to the different density of sand, the weight is not the same
Construction sand is generally about 1.4-1.6 tons per cubic meter;
About 1.4-1.9 tons of dry coarse sand per cubic meter;
The dry fine sand is about 1.4-1.65 tons per cubic meter;
Wet fine sand is about 1.8-2.1 tons per cubic meter;
Gravel 1.4-1.5 tons per cubic meter

The second power of 3x × the fifth power of X - the second power of X × x

3x²×x^5-x²×x
=3x^7-x³

The area of the triangle formed by the vertex of the parabola y = x2-4x + 3 and its intersection with the X axis is______ ．

From the meaning of the problem, we can get: the ordinate of the vertex of the parabola is 4ac − b24a = - 1, ∵ x2-4x + 3 = 0, the solution is X1 = 1, X2 = 3, ∵ the intersection of the parabola and X axis is (1,0), (3,0); from the meaning of the problem, we can get: the vertex of the bottom edge length = | x1-x2 | = 2, ∵ the parabola y = x2-4x + 3 and its intersection with X axis

How to do physics problems about mass and density
When the bottle is full of water, the total mass is 400g; when the bottle is full of alcohol, the total mass is 350g

Let me give you a hint: let the mass of the bottle be XG and the volume be y cubic centimeter,
X + y times the density of water = 400
X + y times the density of alcohol = 350
I think you can do the rest!
Hope to help you!

49 / 51 × 23,

49/51×23
=（1-2/51）×23
=23-46/51
=22 and 5 / 51