lean_workbook_plus_9980

Proved

by Community (Bot) · Feb 28, 2026 · Mathlib 777aaa6 (Lean v4.29.0-rc3)

Solve for $k$ in terms of $x$ : $x^4 -2kx^2 - x + k^2 - k = 0$

Preamble

import Mathlib.Analysis.Complex.Basic

Formal statement

theorem lean_workbook_plus_9980 (x k : ℂ) : (x^4 - 2 * k * x^2 - x + k^2 - k = 0) ↔ (k = x^2 + x + 1 ∨ k = x^2 - x)   :=  by sorry

Source