The square difference of the distance from O (0,0), a (C, 0) is constant, and the trajectory equation of C is?

Let P (x, y),
PO^2=x^2+y^2
PA^2=x^2-2cx+c^2+y^2
|PO^2-PA^2|=c
|2cx-c^2|=c
4c^2x^2-4c^3x+c^4=c^2
C = 0, C ≠ 0
4x^2-4cx+c^2-1=0
[2x-(c+1)][2x-(c-1)]=0
∴x=(c+1)/2,x=(c-1)/2 .

It is known that the constant term of the bivariate quadratic equation (m-1) x ^ 2 + 5x + m ^ 2-3m + 2 = 0 about X is 0, and the value of M is obtained

Constant term is 0? Isn't that easy
m^2-3m+2=0
The solution is m = 1 or M = 2,
Because M-1 is guaranteed to be a quadratic equation of one variable, M-1 cannot be equal to 0
m=2

What was China's steel output in 1958

10.8 million tons

As long as the electrostatic force between point charges is calculated, Coulomb's law can be used. Right?

Generally speaking, this is true, but strictly speaking, the point charge must be in a vacuum and static relative to the observer

October 10, 2011 is Monday. What day is it in 100 days

100²
=(7×14+2)²
=(7×14)²+4×7×14+2²
The first two terms are multiples of 7
So the remainder of 100 & # 178; △ 7 is 2 & # 178; = 4
1+4=5
So it's Friday

Write and balance the following chemical reaction expressions with chemical equations. If you write well, add 100 points
It must be written in chemical equations and balanced
1. Magnesium + oxygen - (ignition) - > magnesium oxide
2. Carbon + oxygen - (ignition) - > carbon dioxide
3. Red phosphorus + oxygen - (ignition) - > phosphorus pentoxide
4. Sulfur + oxygen - (ignition) - > sulfur dioxide
5. Iron + oxygen - (ignition) - > Fe3O4
6. Hydrogen peroxide - (manganese dioxide) - > water + oxygen
7. Potassium chlorate - (heating with manganese dioxide) - > potassium chloride + oxygen
8. Potassium permanganate - (heating) - > potassium permanganate + manganese dioxide + oxygen
9. Water - (on) - > hydrogen + oxygen
10. Iron + copper sulfate > copper + ferrous sulfate
11. Sodium carbonate + hydrochloric acid - > sodium chloride + carbon dioxide + water
12. Paraffin + oxygen - (ignition) - > carbon dioxide + water
If it's well written, 100 points will be added. Thank you
If you can, write the balancing process. If the equation has a process, you can also write

Two magnesium atoms and one oxygen molecule react to form two MgO molecules 2mg + O2 = ignition = 2mgo2. One carbon atom and one oxygen molecule react to form a carbon dioxide molecule C + O2 = ignition = CO23. Four phosphorus atoms and five oxygen molecules are ignited

Calculation of 100022522 − 2482 by factorization=______ ．

The original formula = 10002 (252 + 248) (252 − 248) = 100021000 × 2 = 500

① Take one out of a set of 52 playing cards (excluding king and King), put it back, shuffle it again, and then take out another,
(1) What's the probability that the front and back photos are of the same color?
(2) What's the probability that it's the same?
I calculated the probabilities of 1-4 and 1-52, but the answer is not that
② From 1,2,3 , 100, two numbers randomly selected from a total of 100 numbers,
(1) The probability that the product is a multiple of 9
I figured it out to be 23 / 90, but the answer is wrong
I also think the answer is wrong

I think your results (1 / 4 and 1 / 52) are right
The probability that the first and second cards drawn are all of a certain suit is (1 / 4) * (1 / 4) = 1 / 16. There are four kinds of suits, so there are four kinds of "a certain suit", and * 4 gets 1 / 4. The second is the same as, (1 / 52) * (1 / 52) * 52 = 1 / 52
2. [C (33; 2) + C (11; 1) * C (67; 1)] / C (100; 2) = 23 / 90

159 times 353535 of 5353 minus 105 times 103 of 104. The question is: why is 353535 of 5353 equal to 35 of 5353?

535353=3*7*13*37*53
353535=3*5*7*7*13*37
3 * 7 * 13 * 37 = 10101
535353/10101=53
353535/10101=53
So 535353 / 3535 = 53 / 35

The square difference of the distance from O (0,0), a (C, 0) is constant, and the trajectory equation of C is?