Exercise
The binary operation (x, y) -> x2y on Z is
commutative and associative
commutative but not associative
associative but not commutative
neither commutative nor associative
No: commutativity would mean that
x2y = y2x for all integers x, y.
No: commutativity would mean that
x2y = y2x for all integers x, y.
No: associativity would mean x4y2z =
x2y2z for all integers x, y, z.
Yes.