lean_workbook_plus_69623

Proved

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

Prove: $(3-c)^2+(3-b)^2+(3-a)^2 \geq 12$ -based on the fact that $a+b+c=3$

Preamble

import Mathlib.Analysis.Complex.Basic

Formal statement

theorem lean_workbook_plus_69623 (a b c : ℝ) (h : a + b + c = 3) : (3 - a) ^ 2 + (3 - b) ^ 2 + (3 - c) ^ 2 ≥ 12   :=  by sorry

Source