Find all solutions to .
Answer and explanation
Correct answer: A.
- Step 1: Test odd integers modulo 8: ; .
- Step 2: ; .
- Step 3: All odd residues coprime to 8 satisfy , so the solutions are .
Answer
x = 1, 3, 5, 7 (mod 8).
Why not the others: '' forgets residues 3 and 5; '' omits 3 and 7; '' only tests .
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