a + b = 105
2a/3 = b/2 ==> 4×a = 3×b ==>
==> a = 3×b/4
3×b/4 + b = 105 |×4
3×b + 4×b = 420
7×b = 420
b = 420:7
b = 60
a = 3×60/4 = 3 × 15 = 45
sau metoda grafica:
a /------/------/------/
b /------/------/------/------/
105 : 7 = 15 (un segment egal)
a = 3 × 15 = 45
b = 4 × 15 = 60
verificam:
45 + 60 = 105
