Hello out there! I'm a new guy here, so don't pick on me too much...I cry easy I want to show that a set of units in a ring forms a group under multiplication. What steps would I take to show this? Things that my feable brain knows: 1) if [tex]a[/tex] is a unit, it is invertible and [tex]a^-^1[/tex] is also a unit. 2) the product of units is a unit. 3) and that [tex](ab)^-^1 = b^-^1 a^-^1[/tex] How should I proceed? Thanks in advance for any and all help. Best!