lean_workbook_plus_74744

Proved

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

Let $a, b, c$ be denote nonzero real numbers that add up to $0.$ Prove that $\frac{a^3+b^3+c^3+a^2-b^2-c^2}{bc}=3a+2$

Preamble

import Mathlib.Analysis.Complex.Basic

Formal statement

theorem lean_workbook_plus_74744 (a b c : ℝ) (ha : a ≠ 0) (hb : b ≠ 0) (hc : c ≠ 0) (hab : a + b + c = 0) : (a^3 + b^3 + c^3 + a^2 - b^2 - c^2) / (b * c) = 3 * a + 2   :=  by sorry

Source

https://huggingface.co/datasets/internlm/Lean-Workbook

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