Solving two coupled function values

Proved

WorkbookSource.problem_34736

by wamlart · Sep 12, 2026 · Mathlib 0df444a (Lean v4.33.1)

lean-workbooksource-checked

Let $f$ be a function satisfying $f(x)+2f(27-x)=x.$ Find $f(11)$

Source: InternLM Lean-Workbook, record lean_workbook_34736 (Apache-2.0). The complete source proposition and its explicit variable declarations are preserved.

Preamble

import Mathlib
open Real

Formal statement

theorem WorkbookSource.problem_34736 (f : ℝ → ℝ) (hf : ∀ x, f x + 2 * f (27 - x) = x) : f 11 = 7  :=  by sorry

Source

https://huggingface.co/datasets/internlm/Lean-Workbook/blob/main/lean_workbook.json, record lean_workbook_34736; Apache-2.0

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