It is known that a = a + 2, B = a ^ 2 + A + 5, C = a ^ 2 + 5a-19, where a > 0 (1) try to explain that B-A > 0 Given a = a + 2, B = a ^ 2 + A + 5, C = a ^ 2 + 5a-19, where a > 0 (1) try to explain B-A > 0 (2) judge the size relationship between B and C, and explain the reason

It is known that a = a + 2, B = a ^ 2 + A + 5, C = a ^ 2 + 5a-19, where a > 0 (1) try to explain that B-A > 0 Given a = a + 2, B = a ^ 2 + A + 5, C = a ^ 2 + 5a-19, where a > 0 (1) try to explain B-A > 0 (2) judge the size relationship between B and C, and explain the reason

(1)
B-A
=a^2+a+5-(a+2)
=a^2+a+5-a-2
=a^2+3
Because a ^ 2 ≥ 0, a ^ 2 + 3 ≥ 3 > 0
（2）
B-C
=a^2+a+5-(a^2+5a-19)
=a^2+a+5-a^2-5a+19
=-4a+24
=-4(a-6)
Because - 40, that is, when a > 6, b-c

The first triangle has a perimeter of C and an area of S. its three median lines form the second triangle. The three "topics" of the second triangle are below
The perimeter of the first triangle is C, and the area is s. its three median lines form the second triangle, and the three median lines of the second triangle form the third triangle, and so on. What is the perimeter and area of the second triangle?

According to the law, the perimeter of the first triangle is C and the area is s; the perimeter of the second triangle is C / 2 and the area is s / 4; the perimeter of the third triangle is C / 4 and the area is s / 16 The perimeter of the nth triangle is C / [2 ^ (n-1)], the area is s / [4 ^ (n-1)], and N is a positive integer

[2 minus 0.3x] divided by 0.4 = 0.2x divided by 0.3 minus 1

The denominator of cent is multiplied by 10 at the same time
（20-3X)/4=2X/3-1
3 (20-3x) = 8x-12
Remove brackets to get 60-9x = 8x-12
Transfer merger 17x = 72
X = 72 / 17

A semicircular flower bed, its area is 56.52 square meters, how much is the perimeter of this flower bed?

Because 56.52 × 2 △ 3.14 = 36 (square meters), 6 × 6 = 36. So the radius is 6 meters; the perimeter of flower bed is 3.14 × 6 + 6 × 2, = 18.84 + 12, = 30.84 (meters). Answer: its perimeter is 30.84 meters. So the answer is: 30.84

Calculate (- 128 16 / 37) divided by 32
Negative 128 and 16 / 37 divided by 32?

-297/74

In equilateral triangle ABC, points D and E are on edges BC and AC respectively, and [BD] = 1 / 3 [BC], [CE] = 1 / 3 [Ca], ad and be intersect at point P
Link de
Then the triangle EDC is a right triangle and

Because ∠ DPE = ∠ PBD + ∠ BDP = ∠ DAB + ∠ PDB = 120
Therefore, DPE + ACB = 180
It is proved that the four points of PDEC are in common circle

If the 4-dimensional sequence vector A1 A2 A3 is linearly independent, Bi (I = 1,2,3,4) is nonzero and orthogonal to A1 A2 A3, then R (B1 B2 B3 B4) =?

It is known that the area of a trapezoid is 9 square centimeters, its upper bottom is 4.5 centimeters, its lower bottom is 5.5 centimeters, and how many centimeters is its height. Solve the equation

Set the height to x cm
（4.5+5.5）x/2=9
5x=9
x=1.8

Let a, B ∈ R, and a ≠ 2. If the function f (x) = LG1 + ax1 + 2x defined in the interval (− B, b) is odd, then the value range of a + B is______ ．

∵ the function f (x) = LG1 + ax1 + 2x defined in the interval (- B, b) is odd, ∵ any x ∈ (- B, b), f (- x) = - f (x), that is, LG1 − ax1 − 2x = - LG1 + ax1 + 2x, ∵ LG1 − ax1 − 2x = LG1 + 2x1 + ax, that is, 1-a2x2 = 1-4x2, the solution is a = ± 2, and ∵ a ≠ 2, ∵ a = - 2; then the function f (x) = LG1 − 2x1 + 2x, in order to make the function meaningful, then 1 − 2x1 + 2x The solution of (1 + 2x) (1-2x) > 0 is: - 12 < x < 12, that is, the definition domain of function f (x) is: (- 12, 12), ⊆ (- 12, 12), ⊆ (- B, b) ⊆ (- 12, 12), ⊆, 0 < B ≤ 12 ⊆ - 2 ⊆ - 2 ⊆ - 2 ⊆ - 2 ⊆ - 2 ⊆ - 2 ⊆ - 2 ⊆ - 2 ⊆ - 2 ⊆ a + B ⊆ 32

Conical grain pile, 2 meters, covering an area of 16 square meters. Put this pile of grain into the granary, which just accounts for 2 / 7 of the granary volume. Calculate the granary volume

The volume of millet is 1 / 3 × sh = 1 / 3 × 16 × 1.2 = 6.4 cubic meters
Granary volume = 6.4 / (2 / 7) = 22.4 M3