lean_workbook_plus_9007

Proved

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

Find the roots of the polynomial $x^{4} -12x^{3} +49x^{2} -78x +40$ .

Preamble

import Mathlib.Analysis.Complex.Basic

Formal statement

theorem lean_workbook_plus_9007 (x : ℂ) : x^4 - 12*x^3 + 49*x^2 - 78*x + 40 = 0 ↔ x = 1 ∨ x = 2 ∨ x = 4 ∨ x = 5   :=  by sorry

Source