lean_workbook_plus_57374

Proved

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

Given that $1$ and $-5$ are roots of the cubic equation $2x^3+9x^2-6x-5=0$ , find the third root.

Preamble

import Mathlib.Analysis.Complex.Basic

Formal statement

theorem lean_workbook_plus_57374 (x : ℝ) : (x = 1 ∨ x = -5 → 2*x^3 + 9*x^2 - 6*x - 5 = 0)   :=  by sorry

Source