Răspuns :
18 : ( a × 2 ) = 3
a x 2 = 18 : 3
a x 2 = 6
a = 6 : 2
a = 3
Verific: 18 : ( 3 x 2) = 18 : 6 = 3
a x 2 = 18 : 3
a x 2 = 6
a = 6 : 2
a = 3
Verific: 18 : ( 3 x 2) = 18 : 6 = 3