We will balance equations based on lawvof conservation of mass which means mass of the substanse before and after the reaction must be same. So you have to check no.of atoms are equal on same sides. You have to know how to balance reactions when a particular term in the reactions are mentioned with brackets i.e., for example 2Pb(NO3)2→ PbO+NO2+O2. Here, no.of reactants are not equal to products.. you have to check that in reactants Pb has 2 atoms and in reactants Pb doesnot have 2 atoms. And NO should be written in 2NO2.
So, here is a stichiometric equation(balanced equation)
2PB(NO3)2→2PBO+4NO2+O2. (There is heat ▲ which you can mention it up of the arrow).