On the simple inequality of one variable, a difficult problem, 1. Inequality system x-a>2 The solution set of b-2x > 0 is X

On the simple inequality of one variable, a difficult problem, 1. Inequality system x-a>2 The solution set of b-2x > 0 is X

∵x-a>2,
∴x>2+a
∵x2+a
∴a

As shown in the figure, De is the median line of △ ABC, M is the midpoint of De, and the extension line of CM intersects AB at point n, then s △ DMN: s quadrilateral anme equals ()
A. 1：5B. 1：4C. 2：5D. 2：7

∫ De is the median line of △ ABC, ∥ de ∥ BC, de = 12bc. If the area of △ ABC is 1, according to de ∥ BC, ∥ s ∥ ade = 14, am is connected. According to the title, s ∥ ADM = 12S ∥ ade = 18S ∥ ABC = 18, ∥ de ∥ BC, DM = 14bc, ∥ DN = 14bn, ∥ DN = 13bd = 13ad. ∥ s

How much is the sum of 1 plus 2 plus 2 to the 63rd power of 2

1+2+2^2+2^3+…… +2^63
=(1+2)+2^2+2^3+…… +2^63
=(2^2-1)+2^2+2^3+…… +2^63
=（2^2-1+2^2）+2^3+…… +2^63
=(2^3-1)+2^3+…… +2^63
=…………
=2^64-1

How to use the parameters on the electric energy meter to calculate the maximum power of the electric appliance that can be connected by the circuit and the electric energy meter in general time

This problem is too general. The direct watt hour meter is judged by dividing the current by 2 [three-phase load] or 4.5 [single-phase load]. If it is connected to the watt hour meter through the current transformer, it should be determined according to the rated current of the primary side of the current transformer

It is known that M is an integer, and the system of equations 4x − 3Y = 66x + my = 26 has an integer solution, then the value of M is______ ．

4x − 3Y = 6, ① 6x + my = 26, ② × 2 - ① × 3, we get: (2m + 9) y = 34, the solution is y = 342m + 9, substituting y = 342m + 9 into ①, we get: x = 14 (1022m + 9 + 6) = 3M + 392m + 9, ∵ the system of equations has integer solution, ∵ 2m + 9 = - 1, - 2, - 17, 1, 2, 17, the solution is m = - 5, - 5.5, - 13, - 4, - 3.5, 4

The current through the motor to do 300 J of work, the motor consumption of electric energy______ (fill in "greater than", "equal to" or "less than") 300j, the mechanical energy converted by the motor______ (fill in "greater than", "equal to" or "less than") 300j

The process of using electrical appliances to consume electric energy is also the process of current doing work, that is, the work done by the current through the electrical appliances is equal to the electric energy consumed, so the electric energy consumed by the motor is equal to 300j when the current through the motor does 300j work. Because when the current through the motor, a part of the electric energy must be converted into internal energy, so the mechanical energy converted by the motor is less than 300j The case is: equal to; less than

If x ^ 2 + 2XY + y ^ 2-A (x + y) + 25 is a complete square
If x ^ 2 + 2XY + y ^ 2 - A (x + y) + 25 is a complete square, find the value of A
I forgot everything before. Tell me about it~

The original formula = (x + y) & sup2; - A (x + y) + 25
=(x + y + 5) & sup2; or (x + Y-5) & sup2;
(x+y+5)²
=(x+y)+10(x+y)+25
-a=10
(x+y-5)²
=(x+y)²-10(x+y)+25
-a=-10
So a = - 10, a = 10

Xiao Li will connect two light bulbs marked with 220 V and 40 W in series into the home circuit, then the total power consumed by the circuit is

First of all, the 220 V 40 W marked on the bulb means the rated voltage and rated power. Because it is in series, the terminal voltage of two bulbs is not 220 V, and the power of each bulb is not 40 W. then we can only calculate the resistance of the bulb. Then we can calculate the power. The resistance of the two bulbs must be the same, so the partial voltage after series connection is the same

Simplification: 5 (3a ^ 2b-ab ^ 2) - 4 (- AB ^ 2 + 3A ^ 2b)

5(3a^2b-ab^2)-4(-ab^2+3a^2b)
=15a²b-5ab²+4ab²-12a²b
=3a²b-ab²

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 will not be current in the circuit, so a is wrong. B. the resistance of the conductor does not change with 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. C. according to Ohm's law, the higher the voltage at both ends of the conductor D. as long as there is current flowing through the bulb, there must be voltage at both ends of the bulb, so D is wrong; so C is selected