lean_workbook_plus_37721

Proved

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

Plug in $x=3, y=4$ . We get: $\frac{7x-4y}{3x+y}\implies \frac{21-16}{9+4} \implies \boxed{\frac{5}{13}}$

Preamble

import Mathlib.Analysis.Complex.Basic

Formal statement

theorem lean_workbook_plus_37721 (x y : ℝ) : (x = 3 ∧ y = 4) → (7 * x - 4 * y) / (3 * x + y) = 5 / 13   :=  by sorry

Source