Step-by-step explanation:
Here's a chart for verbs ending in -er
Yo form > Ends with -o > Vivo
Tú form > Ends with -es > Vives
Él/Ella/Usted > Ends with -e > Vive
Nosotros/as > Ends with -imos > Vivimos
Vosotros/as > Ends with -ís (don't forget the accent) > Vivís
Ellos/Ellas/Ustedes > Ends with -en > Viven
Correct me if I'm wrong, it's been a while...
(Ud.) = Usted
(Uds.) = Ustedes