Răspuns :
Înlocuim:
a+3a+3b=130
4a+3*3a=130
4a+9a=130
13a=130
a=10
b=10*3=30
c=30*3=90
a+3a+3b=130
4a+3*3a=130
4a+9a=130
13a=130
a=10
b=10*3=30
c=30*3=90
a+3*a+3*b=130
a+3*a+3*3*a=130
13a=130
a=10
b=3*a
b=3*10=30
ca=3*b=3*30=90
RASPUNS a=10
b=30
c=90
proba 10+30+90=130 corect
a+3*a+3*3*a=130
13a=130
a=10
b=3*a
b=3*10=30
ca=3*b=3*30=90
RASPUNS a=10
b=30
c=90
proba 10+30+90=130 corect