isabelle/valid/amc12a_2002_p1.thy (14 lines of code) (raw):

(* Authors: Wenda Li *) theory amc12a_2002_p1 imports Complex_Main "HOL-Computational_Algebra.Computational_Algebra" "Symmetric_Polynomials.Vieta" begin theorem amc12a_2002_p1: fixes f::"complex \<Rightarrow> complex" assumes "\<forall> x. f x = (2 * x + 3) * (x - 4) + (2 * x + 3) * (x - 6)" shows "(\<Sum> y \<in> f -` {0}. y) = 7/2" sorry end