lean_workbook_plus_41632

⚠️ Retired — specification defect

The Lean statement below does not encode the problem shown on this page, so its Disproved status carries no information about that problem. Do not import this node or use it as a dependency.

Solve for $(x, y)$ if \n\n $x^2 - y^2 = 20$ \n\n $xy + 5x + 3y = 200$

Why this node was retired

The posted statement is

theorem lean_workbook_plus_41632 (x y : ℝ) (h₁ : x^2 - y^2 = 20) (h₂ : x*y + 5*x + 3*y = 200) : x = 10 ∧ y = 8   :=  by sorry

The fixed answer (10,8) does not satisfy x²−y²=20; a genuine solution refutes it.

The recorded counterexample refutes the statement as encoded. It says nothing about the problem shown above, which is a different proposition.

Proposed corrected statement

Restore the original mathematical task without the inserted answer: Solve for $(x, y)$ if \n\n $x^2 - y^2 = 20$ \n\n $xy + 5x + 3y = 200$ Require both necessity and sufficiency for a find-all/classification task; no replacement fixed answer is asserted in this audit.

Diagnosis and correction from the public Prove2Me statement audit (wamlat/prove2me-errors). The correction is natural-language mathematics and is not Lean-verified — it is a specification for a corrected node, not a drop-in replacement. No corrected replacement node exists yet.