Let A= -{-1}, that is, the set of all real numbers except -1. Define an operation on A by a*b=a+b+ab (usual addition and multiplication in R)
a) Show that * is closed on A
b) show that * is associative
c) Find the identity element for * and verify that it is the identity
d) for an element c of A, what is the inverse of c for *? Why?