Given that a root of the equation 4x & # 178; - 5kx + K & # 178; = 0 is x = 2, then K=

Given that a root of the equation 4x & # 178; - 5kx + K & # 178; = 0 is x = 2, then K=

Substitute x = 2 for:
16-10k+k+²=0
（k-8）（k-2）=0
K = 8, or K = 2
The original equation can be solved
Substituting x = 2, the original equation is 16-10k-k ^ 2 = 0
The formula is as follows: (8-K) (2-k) = 0
So k = 2 or K = 8
When m is the value, the two roots of the equation 2x & # 178; - (M & # 178; - 4) x + M = 0 are opposite numbers
According to Weida's theorem:
X1 + x2 = (m ^ 2-4) / 2 = 0, X1 * x2 = m / 2 = - X1 ^ 20, the equation has a solution and meets the requirements,
Therefore, M = - 2 is the required value
According to Weida's theorem and the meaning of the title:
x1+x2=(m²-4)/2=0，x1*x2=m/2≤0
The solution is: M = - 2
I wish you progress in study and happy life!
X ^ 2 + 2aX + B ^ 2 = 0 if a is any one of the four numbers 0.1.2.3 and B is any one of the three numbers 0.1.2, the probability of the equation having real roots?
If the equation has real roots, the discriminant = 4A ^ 2-4b ^ 2 > = 0
That is, a > = b > = 0
There are 12 ways to take 4 * 3 = and 9 ways to take a > = B are (0,0), (1,0), (1,1), (2,0), (2,1), (2,2), (3,0), (3,1), (3,2)
So probability = 9 / 12
If there is a real root, it means △ > = 0, that is, (2a) ^ 2-4 * 1 * B ^ > = 0 --- > A ^ 2 > = B ^ 2
4*3=12
(0.0) compliance
(0.1) non conformity
(0.2) non conformity
(1.0) compliance
(1.1) compliance
(1.2) non conformity
(2.0) compliance
(2.1) compliance
(2.2) compliance
(3.0) compliance
(3.1) compliance
(3.2)... Unfold
If there is a real root, it means △ > = 0, that is, (2a) ^ 2-4 * 1 * B ^ > = 0 --- > A ^ 2 > = B ^ 2
4*3=12
(0.0) compliance
(0.1) non conformity
(0.2) non conformity
(1.0) compliance
(1.1) compliance
(1.2) non conformity
(2.0) compliance
(2.1) compliance
(2.2) compliance
(3.0) compliance
(3.1) compliance
(3.2) compliance
The probability is 9 / 12, which is 3 / 4
On magnetic energy and electric energy and energy,
There are two problems
1. How can magnetic energy be converted into electrical energy?
2. What are the forms of energy in nature? How do they transform?
1. Generator is an example of converting magnetic energy into electrical energy. It is the movement of wire cutting magnetic induction line
2. The forms of energy in nature are: electric energy, solar energy, thermal energy, wind energy, chemical energy, potential energy, kinetic energy. The conversion relationship is too many and too complex
3-phase 380V, current value 2a, power rate 90% of the electric heater power consumption is how much kW
1.732X380X2/0.9=1.46KW
The rule of multiplying negative number by positive number in multiplication
For example, (- 270) × & frac14; + 0.25 × 21.5 + (- 8 & frac12;) × (-% 25) tells us that the simple method can also be urgent!
=（-270）×0.25+0.25×21.5+(-8.5)×（-0.25）
=0.25×[（-270）+21.5+（-8.5）]
=0.25×-257
=-64.25
Use 9 matchsticks to make the figure as shown in the figure. You can move several matchsticks so that the figure they make is the center
Translate the rightmost triangle to the middle of the two triangles on the left, so that the diagonals of the three triangles form a common angle. Isn't that a centrosymmetric figure
It's not very intuitive. Please check the picture below
Move the bottom two sides of the equilateral triangle to the side to form a parallelogram, which becomes a center to form a figure..
The source of electric energy, explain what is wind energy, water energy, heat energy, solar energy, kinetic energy, mechanical energy
Explain what they are or how they transform, be brief and clear
Wind energy: due to the atmospheric temperature and other factors, the pressure in different areas is different, and the air flows from the high pressure area to the low pressure area, forming wind. It is converted into mechanical energy or electric energy by the fan. Water energy: the potential energy formed due to the different height of the water surface is converted into mechanical energy or electric energy by the water turbine
That's a good question
I don't have time
..........................
Nuclear fission material conversion
The dial is marked with 3000r / kW, which means that the work done by the current is w = () kW. H. When the dial turns n, the work done by the current is w = () kW. H = () J
It means that the dial turns 3000 times per kilowatt hour, and the work done by the current of each turn of the dial is w = 1 / 3000kwh
When the dial turns n, the work done by the current is w = n / 3000kwh = n (3600000 / 3000) joules
Negative addition, subtraction, multiplication and division 100!
Q: how to add, subtract, multiply and divide negative numbers fa.hai Negative numbers add, negative numbers subtract, negative numbers multiply, negative numbers divide
Hao de gei jia fen.xuan Negative number addition, subtraction, multiplication and division
1. Addition of negative numbers: the calculation method of addition of negative numbers is the same as that of addition of positive numbers, just adding a negative sign before the result. For example: (- 2) + (- 3) = - (2 + 3) = - 52. Subtraction of negative numbers: in short, subtracting a negative number is equivalent to adding a positive number of that number. For example: - 2 - (- 3) = - 2 + 3 = 3-2 = 1
Even numbers are directly offset and odd numbers are unchanged
（-1）+（-2）= - (1+2)
(- 1) - (- 2) = - 1 + 2 = 1 means that the following two negative signs cancel the subtraction and are equal to the addition
(- 1) × (- 2) = 2 division is the same as multiplication. The key point is to see how many negative signs there are in a formula
Even numbers are directly offset and odd numbers are unchanged
I hope you understand
One hundred and twenty-three
1. Addition of negative numbers: the calculation method of addition of negative numbers is the same as that of addition of positive numbers, just add a negative sign before the result. For example: (- 2) + (- 3) = - (2 + 3) = - 5
2. Subtraction of negative numbers: in short, subtracting a negative number is equivalent to adding the positive number of that number. For example: - 2 - (- 3) = - 2 + 3 = 3-2 = 1. Or: - 3 - (- 2) = - 3 + 2 = 2-3 = - 1
3. Multiplication of negative numbers: the algorithm is the same as multiplication of positive numbers, only considering the sign problem.
If two numbers have the same sign, expand
1. Addition of negative numbers: the calculation method of addition of negative numbers is the same as that of addition of positive numbers, just add a negative sign before the result. For example: (- 2) + (- 3) = - (2 + 3) = - 5
2. Subtraction of negative numbers: in short, subtracting a negative number is equivalent to adding the positive number of that number. For example: - 2 - (- 3) = - 2 + 3 = 3-2 = 1. Or: - 3 - (- 2) = - 3 + 2 = 2-3 = - 1
3. Multiplication of negative numbers: the algorithm is the same as multiplication of positive numbers, only considering the sign problem.
If two numbers have the same sign, the result is positive; if two numbers have opposite sign, the result is negative.
For example: (- 2) * (- 3), both numbers are negative, and the sign is the same, so the result is positive, that is, 6
If: (- 2) * 3 or 2 * (- 3), the sign of two numbers is different, so the result is negative, that is - 6
4. Division of negative numbers: the method is the same as multiplication of negative numbers. First, divide according to the fact that both numbers are positive, and then judge the sign. If two numbers have the same sign, the result is positive; if two numbers have opposite sign, the result is negative.
For example: (- 6) / (- 2), both numbers are negative, and the sign is the same, so the result is positive, that is, 3
If: (- 6) / 2 or 6 / (- 2), the sign of two numbers is different, so the result is negative, that is - 3. (- 1) + (- 2) = - (1 + 2)
(- 1) - (- 2) = - 1 + 2 = 1 means that the following two negative signs cancel the subtraction and are equal to the addition
(- 1) × (- 2) = 2 division is the same as multiplication. The key point is to see how many negative signs there are in a formula
Even number will offset directly, odd number will not change