Răspuns :
c = 2 x g
72 = 7 c + 4 g
72 = 7 (2 x g ) + 4 g
72 = 14 x 7 g + 4 g
72 = 91g + 4 g
72 = 95 g
g = 95 : 72
72 = 7 c + 4 g
72 = 7 (2 x g ) + 4 g
72 = 14 x 7 g + 4 g
72 = 91g + 4 g
72 = 95 g
g = 95 : 72