To find the number of positive integers x satisfying the given conditions, we need to analyze the divisibility condition x2−x by 102006.
1. Condition Analysis:
x2−x≡0(mod102006)
This implies:
x(x−1)≡0(mod102006)
Since 102006=22006×52006, we need:
x(x−1)≡0(mod22006)andx(x−1)≡0(mod52006)
2. **Divisibility by 22006**:
x(x−1)≡0(mod22006)
This means either x≡0(mod22006) or x−1≡0(mod22006). Therefore:
x≡0(mod22006)orx≡1(mod22006)
3. **Divisibility by 52006**:
x(x−1)≡0(mod52006)
This means either x≡0(mod52006) or x−1≡0(mod52006). Therefore:
x≡0(mod52006)orx≡1(mod52006)
4. Combining Conditions Using the Chinese Remainder Theorem:
We need to find the number of solutions x that satisfy both sets of congruences:
- x≡0(mod22006) and x≡0(mod52006)
- x≡0(mod22006) and x≡1(mod52006)
- x≡1(mod22006) and x≡0(mod52006)
Using the Chinese Remainder Theorem, we can solve these systems of congruences:
- For x≡0(mod22006) and x≡0(mod52006):
x≡0(mod102006)
This solution is not valid since x must be positive and less than 102006.
- For x≡0(mod22006) and x≡1(mod52006):
There exists exactly one solution 0<x<102006.
- For x≡1(mod22006) and x≡0(mod52006):
There exists exactly one solution 0<x<102006.
5. Counting the Solutions:
Including x=1, we have:
- One solution from x≡0(mod22006) and x≡1(mod52006)
- One solution from x≡1(mod22006) and x≡0(mod52006)
- The solution x=1
Therefore, there are a total of 3 solutions.
The final answer is 3.