isabelle/valid/amc12a_2015_p10.thy (14 lines of code) (raw):

(* Authors: Albert Qiaochu Jiang *) theory amc12a_2015_p10 imports Complex_Main begin theorem amc12a_2015_p10: fixes x y:: nat assumes h0: "0<y" and h1: "y<x" and h2: "x+y + (x*y) = 80" shows "x=26" sorry end