J.R. S. answered 06/04/21
___C3H8 + ____O2 --->___ CO2 + ____H2O
First balance carbons:
___C3H8 + ____O2 --->___3 CO2 + ____H2O
Next balance hydrogens:
___C3H8 + ____O2 --->___3 CO2 + ____4 H2O
Next balance oxygens:
___C3H8 + ____5 O2 --->___3 CO2 + ____4 H2O and this would be the final balanced equation
C3H8 + 5O2 ==> 3CO2 + 4H2O