adesolavictoria6369 adesolavictoria6369 06-07-2024 Mathématiques résolu 15. The operation * is defined on the set Rof real numbers by a*b=a+b/5-1 for all a,bER. (a) Is R closed under * ?(b) Is the operation * commutativein R?(c) Is the operation * associative inR?