Răspuns:
Salutare!
308×17-b=878
5 236-b=878
b=5 236-878
b=4 358
v:307×17-4 358=5 236-4 358=878
c-256×34=398
c-8 704=398
c=398+8 704
c=9 102
v:9 102-256×34=9102-8704=398
#Succes!