Subtract equations for any two solutions and cancel nonzero a to prove uniqueness.
Step identifiers and dependencies
Rule: unique_solution · Uses: G001, S005
Reverse checks
S006 · premise_and_result_audit — Substitute into the original equation; retain every nonzero condition before division.
S005 · premise_and_result_audit — Recompute a·x+b with exact rational arithmetic, not rounded decimals.
S004 · premise_and_result_audit — Recompute a·x with exact rational arithmetic, not rounded decimals.
S003 · premise_and_result_audit — Recompute x with exact rational arithmetic, not rounded decimals.
S002 · premise_and_result_audit — Substitute into the original equation; retain every nonzero condition before division.
S001 · premise_and_result_audit — Substitute into the original equation; retain every nonzero condition before division.
Result
13
The full substitutions and premise audits recover the original answer, retaining its field order and verdict meanings.
This question review and source binding
Review date: 2026-10-26
Original questions, answers, step expressions, numeric ASTs and historical records are retained. Source candidate labels remain historical and are not overwritten as formal proof.