lean_workbook_plus_21311

Proved

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

Solve the quadratic equation: $x^2+3x+1=0$

Preamble

import Mathlib.Analysis.Complex.Basic

Formal statement

theorem lean_workbook_plus_21311 (x : ℝ) : x^2 + 3*x + 1 = 0 ↔ x = (-3 + Real.sqrt 5)/2 ∨ x = (-3 - Real.sqrt 5)/2   :=  by sorry

Source