lean_workbook_plus_42434

import Mathlib.Analysis.Complex.Basic

theorem lean_workbook_plus_42434 (a b c : ℝ) (ha : a ≠ 0) (hb : b ≠ 0) (hc : c ≠ 0) (hab : 3*a = 4*b) (hbc : 5*b = 6*c) : c/(a+b) = 5/14   :=  by sorry