Math Problem Statement
Find all x in the range 0 to 29 such that: x^2 = x (mod 30)
Solution
To solve for all values of in the range such that:
we start by rearranging the equation:
This can be factored as:
Thus, must be divisible by 30. Since , must be divisible by 2, 3, and 5.
Step 1: Analyzing for Divisibility by 2, 3, and 5
Since and are consecutive integers, one of them is always even, so is divisible by 2.
Similarly, one of or must be divisible by 3.
Finally, for to be divisible by 5, either or must be divisible by 5.
Step 2: Possible Solutions
The divisibility requirements imply that must satisfy the following conditions:
- or must be divisible by 2, 3, and 5.
- This occurs when or .
Step 3: Valid Solutions in the Given Range
Since we only need solutions for , we check:
Verification
-
For :
-
For :
Both values satisfy the condition .
Conclusion
The solutions are:
Would you like a deeper explanation of any part of this solution?
Here are five related questions to further explore modular arithmetic and divisibility:
- How would you solve for in ?
- Can you determine all values of such that for different values of ?
- What are other interesting properties of solutions to equations of the form ?
- How can we use the Chinese Remainder Theorem to solve similar modular equations?
- What happens to the solutions if we expand the range to ?
Tip: Modular equations often simplify by factoring and analyzing each factor's divisibility conditions.
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Math Problem Analysis
Mathematical Concepts
Modular Arithmetic
Divisibility
Congruences
Formulas
x^2 ≡ x (mod n) implies x(x - 1) ≡ 0 (mod n)
Theorems
Divisibility Rules
Chinese Remainder Theorem (implicitly relevant)
Suitable Grade Level
Grades 10-12
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