Răspuns :
a+b+c=1080
b=4a
c=5a
a+4a+5a=1080
10a=1080
a=108
b=4a=432
c=5a=540
verificare
108+432+540=1080
b=4a
c=5a
a+4a+5a=1080
10a=1080
a=108
b=4a=432
c=5a=540
verificare
108+432+540=1080
a + b + c = 1080
b = 4a
c = 5a
a + 4a + 5a = 1080
10a=1080
a=108
b=4*108
b=432
c=5*108
c=540
b = 4a
c = 5a
a + 4a + 5a = 1080
10a=1080
a=108
b=4*108
b=432
c=5*108
c=540