LG is the logarithm of 2 as low as 3 multiplied by log is the logarithm of 3 as low as 5

LG is the logarithm of 2 as low as 3 multiplied by log is the logarithm of 3 as low as 5

Log2 (3) * log3 (5) = (Lg3 / LG2) * (lg5 / Lg3) = lg5 / LG2 = log2 (5)
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Given X & # 178; + 2XY + Y & # 178; - x-y-12 = 0, find the value of X + y

Let x + y = U
(x+y)²-(x+y)-12=0,
That is U & # 178; - U-12 = 0,
Factorization of technetium (U-4) (U + 3) = 0,
We can get u = 4 or u = - 3,
That is, x + y = 4 or x + y = - 3

How much is the actual power of a 220 V · 40 W lamp when it is connected to a 220 V circuit? What is the current passing through? What is the resistance of the lamp? What is the actual power when it is connected to a 110 V circuit?

The rated power will not change with the change of voltage, it is still 40W
Because P = u ^ 2 / R
So r = u ^ 2 / P = (220V) ^ 2 / 40W = 1210 Ω
P actual = u ^ 2 actual / r = (200V) ^ 2 / 1210 Ω≈ 33W

Given (a + 2) ^ 2 + (3b-3) ^ 2 = 0, find the value of 3A ^ 2 - [2Ab ^ 2-6 (1a ^ 2b of ab-2) - 2Ab

If one is greater than 0, the other is less than 0
So both are equal to zero
So a + 2 = 0, 3b-3 = 0
a=-2,b=1
The original formula = 3A & # 178; - 2Ab & # 178; + 6ab-3a & # 178; B + 2Ab
=3a²-2ab²+8ab-3a²b
=12+4-16-12
=-12

About current, voltage and resistance, the following statement is correct ()
A. As long as the conductor is connected to the circuit, there will be current in the circuit. B. the greater the current passing through the conductor, the smaller its resistance. C. The greater the voltage at both ends of the conductor, the greater the current passing through the conductor. D. for a small bulb with current passing through, there is not necessarily voltage at both ends

A. If the circuit is closed and there is voltage in the circuit, there will be current in the circuit. If the conductor is connected into the circuit, there may not be current in the circuit, so a is wrong. B. the resistance of the conductor does not change with the change of the current. The greater the current passing through the conductor, the greater the voltage at both ends of the conductor. It does not mean that the resistance of the conductor is smaller, so B is wrong

The classroom is 10m in length, 6m in width and 3M in height. The lower part of the four walls is painted with 1.2m high paint. What is the paint area? The upper part of the four walls and the roof are painted with white paint
Among them, the window occupies 8 square meters without painting, the door area is ignored, and how many square meters is the area of painting white paint?

First of all, the area below 1.2 meters from the ground does not include the area of the window, so the part is composed of 4 sides, 2 in the length direction and 2 in the width direction, so the area is 2 * (1.2 * 10 + 1.2 * 6) = 38.4 square meters; if the height is above 1.2 meters and the roof is painted white, it is 3-1.2 = 1.8 meters, then the part is composed of 1.2

There is an energy saving lamp used in 220 V circuit, the rated power is only 1 W

I=P/U=1/220v=0.0045A

When a = half, B = one third, 2a and 178; b-6ab% &178; =?

5999/6000

Compared with the same mass of lead and aluminum, whose density is larger and whose volume is larger

First, the masses are known to be equal;
Secondly, the density relation is ρ Pb > ρ al;
Furthermore, from v = m / ρ, we can know that the volume relation is v Pb < V al

What is the calculation formula of VAT?
Is it X / (1 + 17%) * 17%
If it is (1 + 17%), what does it mean?

Conversion of price including tax and price excluding tax
Price excluding tax = price including tax / (1 + collection rate) = x / (1 + 17%)
VAT payable = price excluding tax * tax rate = x / (1 + 17%) * 17%
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