[tex]\it \left.\begin{aligned}\it a+b+c=978512\\ \\ \it b+c=516514\end{aligned}\right\} \Rightarrow a+516514 = 978512|_{-516514} \Rightarrow a=461998\\ \\ \\ \left.\begin{aligned}\it a+b+c=978512\\ \\ \it a+b=634512\end{aligned}\right\} \Rightarrow 634512+c = 978512|_{-634512} \Rightarrow c=344000[/tex]
