Răspuns :
ab=216
bc=648
1/2c=6+a=>c=12+2a
b(12+2a)=648=>b=648/(12+2a)
648a/(12+2a)=216
648a=216(12+2a)
648a=2592+432a
216a=2592
a=12
c=12+24=36
b=648/36=18
a×b=216⇒a=216:b
b×c=648⇒c=648:b
1/2×c=a+6
c=2a+12
648:b=12+2a
648:b=12+2×216:b
648=12b+2×216
648-432=12b
b=216:12
b=18
a=216:b=216:18=12
a=12
c=2a+12
c=24+12=36
a=36
b×c=648⇒c=648:b
1/2×c=a+6
c=2a+12
648:b=12+2a
648:b=12+2×216:b
648=12b+2×216
648-432=12b
b=216:12
b=18
a=216:b=216:18=12
a=12
c=2a+12
c=24+12=36
a=36