+3
a |-----|---|
-3
b |---------|---|
c |----|----| cele doua seg de la c sunt egale
d |---------|----------| cele doua seg de la d sunt egale
a+b+c+d = 63
a+3=b-3=2c = d/2
a+3=b-3 |+3
a+6=b
a+3=2c | :2
a+3supra 2= c
a+3=d/2 |×2
2a +3=d
a+a+6+a+3supra2 +2a+6=63 amplificam cu doi
2a+2a+12+a+3+4a+12=126
9a + 27= 126 | - 27
9a= 99 |:9
a= 11
b=11+6=17
c=14/2=7
d= 2×11+6=28
verificare: 11+17+7+28=28+7+28=56+7=63