Currently Secure · last touched 2026-09-08
| When | Change | Evidence | Session |
|---|---|---|---|
| 2026-09-08 | Secure → Secure | 8 Sep starter: 3a² − 2b with a = −2, b = 5 → 2. (−2)² = +4 handled correctly — the classic substitution trap avoided. Ageing check passed after 9 weeks. | session 11 |
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