lean_workbook_plus_34228

Proved

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

Let $a,b>0$ such that $\frac{4}{a+b}+\frac{1}{b}=1$ . Prove that $a(2b-3)\leq 9$

Preamble

import Mathlib.Analysis.Complex.Basic

Formal statement

theorem lean_workbook_plus_34228 (a b : ℝ) (ha : 0 < a) (hb : 0 < b) (hab : 4 / (a + b) + 1 / b = 1) : a * (2 * b - 3) ≤ 9   :=  by sorry

Source