Răspuns :
a+6b=2b+c
a+6b-2b-120=0
a+4b=120
a=120-4b
a+4b+5c-719
120-4b+4b+5*120-719
120+600-719
720-719=1
a+6b-2b-120=0
a+4b=120
a=120-4b
a+4b+5c-719
120-4b+4b+5*120-719
120+600-719
720-719=1
a+6b = 2b+c
c=120
a+6b = 2b +120
a+4b=120
E=a+4b+5c-719
E= 120 + 120 x5-719
E = 120 + 600 - 719
E = 1
c=120
a+6b = 2b +120
a+4b=120
E=a+4b+5c-719
E= 120 + 120 x5-719
E = 120 + 600 - 719
E = 1