(* Authors: Wenda Li *) theory mathd_algebra_59 imports Complex_Main begin theorem mathd_algebra_59: fixes b :: real assumes "4 powr b + 2^3 = 12" shows "b=1" proof - have "4 powr b = 4" using assms by auto then have "log 4 (4 powr b) = log 4 4" by auto then show ?thesis by simp qed end