Answer
$2Ag_2O(l)\rightarrow 4Ag(s)+O_2(g)$
Work Step by Step
The basic reaction is:
$Ag_2O(l)\rightarrow Ag(s)+O_2(g)$
Add a coefficient of 2 to $Ag_2O$ to balance $O$.
$2Ag_2O(l)\rightarrow Ag(s)+O_2(g)$
Add a coefficient of 4 to $Ag$ to balance $Ag$.
$2Ag_2O(l)\rightarrow 4Ag(s)+O_2(g)$
