Quadratic Congruences Mod 8: How to Solve?

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In summary, a quadratic congruence is an equation in the form of ax^2 + bx + c ≡ 0 (mod m) that involves a quadratic term and can have zero, one, or two solutions depending on the discriminant. To solve it, one can use methods such as the quadratic formula, completing the square, or factoring, and it has various real-world applications in number theory, cryptography, and computer science.
  • #1
Shay10825
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Homework Statement



Hello everyone!

How would you solve a quadratic or nth degree congruence? For example how would I solve:


(x^2) + 2x -3 = 0 (mod 8 )


The Attempt at a Solution



I know this can be written like:

(x^2) + 2x = 3 (mod 8 ) but where would I go from here? and would I use the same approach for nth degree congruencies?

Thanks
 
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  • #2
I don't think there is any approach for nth degree congruencies. mod 8 there are only 8 candidates for x. I suggest you try them all.
 

1. What is a quadratic congruence?

A quadratic congruence is an equation in the form of ax^2 + bx + c ≡ 0 (mod m), where a, b, c, and m are integers and m is a positive integer. It is a type of congruence equation that involves a quadratic term.

2. How do you solve a quadratic congruence?

To solve a quadratic congruence, you need to use a combination of algebraic manipulation and number theory concepts. The general approach is to reduce the equation to a simpler form and then use the quadratic formula or other methods to find the solutions.

3. What are the possible solutions to a quadratic congruence?

A quadratic congruence can have zero, one, or two solutions. The number of solutions depends on the discriminant (b^2 - 4ac) of the equation. If the discriminant is a perfect square, then there are two distinct solutions. If the discriminant is not a perfect square, then there are no solutions.

4. Are there any specific methods for solving quadratic congruences?

Yes, there are several methods for solving quadratic congruences, including the quadratic formula, completing the square, and factoring. Some equations may also require the use of modular arithmetic concepts, such as the Chinese Remainder Theorem.

5. How are quadratic congruences used in real-world applications?

Quadratic congruences have various applications in number theory, cryptography, and computer science. They are used to solve problems related to modular arithmetic and to create secure encryption algorithms. They also have applications in error-correcting codes and pseudorandom number generation.

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