question from chapter 4 PAGE 70 Second Edition Computability, Complexity, and Languages Fundamentals of Theoretical Computer Science by Martin D. Davis, Ron Sigal, and Elaine J. Weyuker

The question :

Book pages :

6. Let x if Goldbach's conjecture is true fox) otherwise. 0 Show that fox) is primitive recursive 6. Let x if Goldbach's conjecture is true fox) otherwise. 0 Show that fox) is primitive recursive