System of linear congruences Help, please

In summary, a system of linear congruences is a set of equations involving modular arithmetic, where the solutions must satisfy a specific remainder when divided by a given number. To solve these systems, techniques such as substitution, elimination, or the Chinese Remainder Theorem can be used. The Chinese Remainder Theorem is a mathematical theorem that provides a method for solving systems of linear congruences with relatively prime moduli. Systems of linear congruences have various applications but may have limitations, such as requiring relatively prime moduli and the possibility of no solution if the congruences are not consistent.
  • #1
MathExpert
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0
5x == 200 (mod 251)
11x == 192 (mod 401)
3x == -151 (mod 907)
 
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  • #2
first find the inverses of 5, 11 and 3 modulo 251, 401, 907 resp. to make it easier to solve. do this using eulcid's algorthim if you do'nt see what the inverse are straigh away. hint 5*50=250, and 3*302=906.

then use the chinese remainder theorem on the first two to reduce to two equivalences, then repeat.
 
  • #3


A system of linear congruences is a set of equations that involve modular arithmetic, where the unknown variable is congruent to a given value modulo a certain number. In this case, the system involves three equations with the unknown variable x, and each equation is congruent to a different value modulo a different number.

To solve this system, we can use the Chinese Remainder Theorem, which states that if the moduli (in this case, 251, 401, and 907) are pairwise coprime (meaning they have no common factors), then there exists a unique solution to the system.

First, we can simplify each equation by dividing both sides by the coefficient of x. This will give us the following system:

x == 40 (mod 251)
x == 192 (mod 401)
x == 252 (mod 907)

Next, we can use the Extended Euclidean Algorithm to find the inverse of each modulus. This will give us the following values:

251^-1 = 4 (mod 401)
401^-1 = 201 (mod 251)
907^-1 = 253 (mod 251)

Using these values, we can now apply the Chinese Remainder Theorem to solve the system. The solution will be given by the following formula:

x = (40*401*201 + 192*251*4 + 252*907*253) (mod 251*401*907)

Simplifying this, we get:

x = 5 (mod 907)

Therefore, the solution to this system of linear congruences is x = 5 (mod 907). I hope this helps!
 

FAQ: System of linear congruences Help, please

What is a system of linear congruences?

A system of linear congruences is a set of equations that involve modular arithmetic, where the variables are congruent to a certain value modulo a given number. In other words, the solutions to the equations must satisfy a specific remainder when divided by the given number.

How do you solve a system of linear congruences?

To solve a system of linear congruences, you can use techniques such as substitution, elimination, or the Chinese Remainder Theorem. These methods involve finding the common solution(s) that satisfy all of the congruences in the system.

What is the Chinese Remainder Theorem?

The Chinese Remainder Theorem is a mathematical theorem that provides a method for solving a system of linear congruences with relatively prime moduli. It states that if the moduli are pairwise relatively prime, then there exists a unique solution to the system of congruences.

Why are systems of linear congruences important?

Systems of linear congruences have applications in fields such as cryptography, number theory, and computer science. They can also be used to solve problems involving modular arithmetic, which is useful in many real-world situations.

Are there any limitations to solving systems of linear congruences?

Yes, there are limitations to solving systems of linear congruences. One limitation is that the moduli in the system must be relatively prime in order for the Chinese Remainder Theorem to be applicable. Additionally, the system may not have a solution if the congruences are not consistent with each other.

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