lean_workbook_plus_25051

import Mathlib.Analysis.Complex.Basic

theorem lean_workbook_plus_25051 (a b c d : ℝ) (f : ℝ → ℝ) (hf: f = fun x : ℝ => x^4 + a*x^3 + b*x^2 + c*x + d) : f 1 = 10 ∧ f 2 = 20 ∧ f 3 = 30 → (f 12 + f (-8)) / 10 = 1984   :=  by sorry