What are the units of Z? In other words find Z^x.
Here is some background:
Every element in a ring has an additive inverse, but only some elements
have multiplicative inverses. Any element with a multiplicative inverse is
called a
unit. Recall that we assume all rings have a multiplicative identity.
Let R be a ring with multiplicative identity 1. If a, b eR are
such that ab = ba = 1 then we say that a and b are multiplicative inverses.
An element a e R is called a unit if it has an inverse. The set of units is
written R:
R^x = {u e R | u is a unit}