Answer
$2\ C_3H_7OH(l)+9\ O_2(g)\rightarrow6\ CO_2(g)+8\ H_2O(g)$
Work Step by Step
$2\ C_3H_7OH(l)+xO_2(g)\rightarrow6\ CO_2(g)+yH_2O(g)$
C: $2\times3 =6 $
H: $2\times(7+1)=y\times2\rightarrow y=8$
O: $2\times1+x\times2=6\times2+y\rightarrow x=9$
$2\ C_3H_7OH(l)+9\ O_2(g)\rightarrow6\ CO_2(g)+8\ H_2O(g)$