Simplify evaluation (2x of x-2x) divided by (1-x + 1 molecule x) - (x of x-2x of x-4) emergency

Simplify evaluation (2x of x-2x) divided by (1-x + 1 molecule x) - (x of x-2x of x-4) emergency

(2x of the square-2x of x) divided by (1-x + 1 molecule x) - (2x of the square-4 of x) = 2x / (X & # 178; - 2x) / [1-x / (x + 1)] - (X & # 178; + 2x) / (X & # 178; - 4) = 2x / X (X-2) / (x + 1-x) / [(x + 1) - x (x + 2) / [(x + 2) (X-2)] = 2 / (X-2) / / 1 / (x + 1) - X / (X-2) = (2x + 2-x) / [(X-2) =

It is known that the square of X - 3x - 1 = 0, and x > 0

If X & sup2; - 3x-1 = 0 and x > 0, divide by X & sup2;, on both sides of the equation;,
The result is: x-3-1 / x = 0
So: X-1 / x = 3;
The square of both sides is: X & sup2; - 2 + 1 / X & sup2; = 9;
That is X & sup2; + 1 / X & sup2; = 11, X & sup2; + 1 / X & sup2; + 2 = 11 + 2;
So: (x + 1 / x) & sup2; = 13,
Square root, take the arithmetic square root, get x + 1 / x = √ 13 [root 13]

Given that the square of X - 3x + 1 = 0, then the value of the square of the cubic of X - X - 5x + 2012

The square of X - 3x + 1 = 0
The three sides of X - the square of X - 5x + 2012
=x³-3x²＋x+2x²-6x+2012
=X (square of X - 3x + 1) + 2 (square of X - 3x + 1) + 2010
=0+0+2010
=2010

Given (x + a) (x + b) = x2-13x + 36, then the value of a + B is ()
A. 13B. -13C. 36D. -36

(x + a) (x + b) = x2 + (a + b) x + AB, and ∵ (x + a) (x + b) = x2-13x + 36, so a + B = - 13

The buoyancy of a ball weighing 88.2n is 78.4n when it is put into oil
When a ball weighing 88.2n is put into oil, the buoyancy at rest is 78.4n. If the ball is put into water, the buoyancy at rest is many n?
(the density of oil is 0.8 * 10 cubic kg / M & sup3;)

Because the buoyancy is less than gravity, the ball sinks into the bottom of the container
The buoyancy is equal to the weight of the liquid
That is to say:
78.4N/0.8*1.0=98 N

Three prisms, four prisms, five prisms, how many sides do they have?

Bottom side
Triangular prism 2 3
Four prisms
Pentaprism 2 5

In the plane rectangular coordinate system xoy, point P is a moving point on the curve y = - x ^ 2 + 1 in the first quadrant, and the tangent line at point P intersects two coordinate axes at two points AB, then what is the minimum area of triangle AOB

The tangent equation is y = - 2xp * (x-xp) + YP, 1 > XP > 0,1 > YP > 0
The intersection point with the coordinate axis is: (0,2xp ^ 2 + YP), ((2xp ^ 2 + YP) / (2 * XP), 0)
Because XP ^ 2 + YP = 1
The intersection point with the coordinate axis is: (0,1 + XP ^ 2), ((1 + XP ^ 2) / (2 * XP), 0)
Area = (1 + XP ^ 2) * [(1 + XP ^ 2) / (2 * XP)] / 2
=(1+Xp^2)^2/(4Xp)
=(1/4)*(1/Xp+2Xp+Xp^3)
f'=(1/4)*(-1/Xp^2+2+3Xp^2)=0
The minimum value is obtained when XP = √ 3 / 3
The minimum area is 4 √ 3 / 9

What is the mix proportion of C10, C15, C20, C25, C30 concrete and the mass of each mixture corresponding to one cubic meter?
How to transform the mass and volume of concrete mixture?

Unit: 1m3 concrete
Project unit: ordinary concrete
Maximum particle size of gravel (mm)
twenty
Concrete grade
15 20 25 30 35 40 45 50
Cement grade
325 325 425 325 425 325 425 425 525 425 525 525 525
1 2 3 4 5 6 7 8 9 10 11 12 13
1 cement kg 294 354 297 412 343 474 390 436 383 482 424 464 504
Medium (coarse) sand m3 0.50 0.48 0.50 0.46 0.49 0.44 0.47 0.46 0.48 0.45 0.47 0.46 0.44
3 gravel m3 0.88 0.84 0.88 0.80 0.85 0.77 0.82 0.80 0.84 0.79 0.81 0.79 0.77
4 rubble m3 -————————————
Unit: 1m3 concrete
Project unit: ordinary concrete
Maximum particle size of gravel (mm)
forty
Concrete grade
10 15 20 25 30 35 40
Cement grade
325 325 425 325 425 325 425 325 425 425 525 425 525
14 15 16 17 18 19 20 21 22 23 24 25 26
1 cement kg 255 282 255 338 273 390 318 432 365 406 350 447 387
Medium (coarse) sand m3 0.52 0.51 0.52 0.49 0.52 0.47 0.50 0.46 0.49 0.48 0.50 0.47 0.49
3 gravel m3 0.910.890.910.850.900.820.870.810.850.830.870.820.820.85
4 rubble m3 -————————————
Unit: 1m3 concrete
Project unit ordinary concrete underwater concrete waterproof concrete pumping concrete rubble concrete
Maximum particle size of gravel (mm)
40 80 40 20 80
Concrete grade
45 50 10 15 20 20 25 25 15 20 15
Cement grade
525 525 325 325 325 325 425 325 425 425 325 325 325
27 28 29 30 31 32 33 34 35 36 37 38 39
1 cement kg 424 461 255 277 331 446 360 515 420 365 344 411 235
Medium (coarse) sand m3 0.47 0.46 0.52 0.52 0.49 0.47 0.53 0.45 0.50 0.49 0.60 0.57 0.44
3 gravel m3 0.830.810.910.900.860.690.780.660.740.850.730.700.77
4 rubble m3 -- 0.21
Unit: 1m3 concrete
Project unit pumping concrete
Maximum particle size of gravel (mm)
20 40
Concrete grade
20 25 30 35 40 45 50 10 15
Cement grade
425 325 425 325 425 425 525 425 525 525 525 325 325
40 41 42 43 44 45 46 47 48 49 50 51 52
1 cement kg 345 474 395 531 437 484 425 530 466 506 544 300 330
Medium (coarse) sand m3 0.60 0.55 0.58 0.53 0.57 0.56 0.58 0.54 0.56 0.55 0.54 0.62 0.61
3 gravel m3 0.730.670.710.6500.700.680.700.660.690.670.6500.750.74
4 rubble m3 -————————————
Unit: 1m3 concrete
Project unit pumping concrete
Maximum particle size of gravel (mm)
forty
Concrete grade
15 20 25 30 35 40 45 50
Cement grade
425 325 425 325 425 325 425 425 525 425 525 525 525
53 54 55 56 57 58 59 60 61 62 63 64 65
1 cement kg 298 392 317 449 366 484 409 451 389 492 426 462 498
2 (coarse) sand kg 0.62 0.58 0.61 0.56 0.60 0.56 0.58 0.57 0.59 0.56 0.58 0.57 0.56
3 gravel m3 0.76 0.71 0.75 0.69 0.73 0.68 0.71 0.70 0.73 0.68 0.71 0.68 0.71 0.69 0.68
4 rubble m3 -————————————
Note:
(1) When fine sand is used to prepare concrete, the cement consumption per cubic meter of concrete increases by 4%;
(2) The cement consumption of various concrete grades listed in the table is calculated by machine tamping. If manual tamping is used, the cement consumption per cubic meter of concrete shall be increased by 25kg;
(3) The consumption of materials has included the in site transportation and operation loss;
(4) The cement consumption per cubic meter of underwater structure of highway shall not be less than 240kg by mechanical tamping and 265kg by manual tamping;
(5) When concrete is transported by pump, the transportation and operation loss of concrete is calculated as 4%;
(6) When concrete is transported by pump, the mixing and curing water for every 10m3 of concrete is as follows:
Cast in place concrete foundation 18m3, cast in place Concrete Superstructure 21m3
Cast in situ concrete substructure 18m3, precast concrete 22m3

Let a B belong to R, and 2A + B-2 = 0, then what is the minimum value of 4 ^ A + 2 ^ B

2a+b=2
4 ^ A + 2 ^ B = (2 ^ 2) ^ A + 2 ^ B = 2 ^ 2A + 2 ^ b > = 2 radical (2 ^ 2A * 2 ^ b) = 2 radical [2 ^ (2a + b)] = 2 * 2 = 4
When 2 ^ 2A = 2 ^ B, that is, 2A = B, take the equal sign
2A + B = 2, then 2A = b = 1,
So we can get the equal sign
So the minimum value is 4

I want to know how many powers are equal to how many powers, and how to convert them?
I want to know how many powers like this are equal to how many powers, and how to convert them?

This is because 4 = 2 ^ 2
4^2=(2^2)^2=2^(2*2)=2^4
Another example is 9 ^ 3 = (3 ^ 2) ^ 3 = 3 ^ (2 * 3) = 3 ^ 6
Note the formula A ^ (B + C) = (a ^ b) * (a ^ C)