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If 2-I is a root of the real coefficient equation x & # 178; + ax + B = 0 about X, then the sum of the modules of the two equations is?
The roots of real coefficient equations are conjugate imaginary numbers
So | x1 | = | x2|
So the sum of modules = 2|2-i|
=2√(2²+1²)
=2√5
If 2-I is a root of the real coefficient equation x & # 178; + ax + B = 0, then the sum of the two modules of the equation is?
If the process is complete, there will be bonus points
Since 2-I is a root, 2 + I is also a root (let P (z) be on the left, then p conjugate (z) = P (Z conjugate), that is, 0 = P conjugate (2-I) = P (conjugate of 2-I) = P (2 + I). This should be a theorem or something.) so the sum of two modules is | 2-I | + | 2 + I | = √ 5 + √ 5 = 2 √ 5 or substitute 2-I in: 4-1-4i + 2
Reaction equation of elemental Si with NaOH solution
Si + 2 NaOH + H2O = Na2SiO3 + 2 H2↑
Chemical equation for the reaction of Si with NaOH solution
Si+2NaOH+H2O=Na2SiO3+2H2↑
What is the common solution of two binary linear equations?
For example, x + y = 3, x = 1, then x of the system of equations with common solution is equal to 1
Help me solve a system of linear equations with two variables!
Given that the sum of solutions of the equations 2x + 3Y = k, 3x + 5Y = K + 1 is - 12, find the value of K. (there must be a specific process)
x+y=-12
1)2x+3y=k
2)3x+5y=k+1
1) * 2 gives 3): 4x + 6y = 2K
3) The result is: x + y = k-1
k-1=-12
k=-11
How many solutions are there for the system of linear equations of two variables? Why?
Such as the title
Because there is a pair of unknowns and a pair of relations, there is a pair of solutions
Using elimination method to solve binary linear equations
4x-7y=20 2x-3y=8
2x-y=4 x+y=2
3s+2t-12=0 3s-t-3=0
5x-2y=3 7x+6y=2
5x-2y=-4 2x-3y=5
4x-7y = 20 2x-3y = 8, then multiply by 2 and want to subtract
2x-y = 4 x + y = 2
3S + 2t-12 = 0 3s-t-3 = 0
5x-2y = 3 7x + 6y = 2 multiply by 3 add
5x-2y = - 4 2x-3y = 5 the former is multiplied by 3 and the latter by 2
Not yet
The method of solving binary linear equations
The first equation is transformed into how much y is equal to x, or how much x is equal to y, and then the resulting X or Y is brought into the second equation
How to solve the equation of water flow in the first day of junior high school?
Equation learning is not very good, especially on the flow equation
For example:
The speed of a passenger ship in still water is 18 kilometers per hour, and the current speed is 5 kilometers per hour. How many kilometers can this passenger ship travel in 4 hours
x/4=18+5
x=72+20
x=92
The passenger ship can travel 92 kilometers in 4 hours
I want to know how to solve this type of problem and why to add the speed of passenger ship to the speed of water
Hope there are experts to explain
Just remember two formulas for this kind of problem. Understand and remember
Downstream speed = speed of ship in still water + water speed
Speed against water = ship's speed in still water - speed of water
For the above problem, because the ship is sailing downstream, the downstream speed = the speed of the ship in still water + the water speed
First, find out the water speed is 23, and then find the distance. Naturally, I think of the formula of distance speed and time. Multiply the speed by time, so it's 23 * 4 = 92
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