f + b = 23
(b-3) : 2 = 3×f : 4 |×4
(b-3) ×2 = 3×f ==>
==> f = (b-3)×2 : 3 =
= (2×b -6) : 3
f |_____|_____| - 2
b |_____|_____|_____|
23 + 2 = 25
25 : 5 = 5 (un segment egal)
f = 2 × 5 - 2 = 10 - 2 = 8 (fete)
b = 3 × 5 = 15 (baieti)
Verificare:
8 + 15 = 23
(15 - 3) : 2 = 3 × 8 : 4
12 : 2 = 24 : 4)
6 = 6 (adevarat