a : 4 = a : 2 - 82
a : 2 - a : 4 = 82
Metoda grafica:
a : 2 /------/------/
a : 4 /------/
2 segmente egale - 1 segment egal = 1 segment egal = 82
a : 2 = 2 × 82 = 164
a : 4 = 82
a = 82 × 4 = 328 (numarul cautat)
Verificam:
328 : 4 = 328 : 2 - 82
82 = 164 - 82
82 = 82
Metoda algebrica:
a : 4 = a : 2 - 82 |×4
a = 2×a - 328
2×a - a = 328
a = 328
