Răspuns :
5 × X - 15 = 0
5 × X = 0 + 15
5 × X = 15
X = 15 : 5
X = 3
Verificare :
5 × 3 - 15 =
15 - 15 = 0
5 × X = 0 + 15
5 × X = 15
X = 15 : 5
X = 3
Verificare :
5 × 3 - 15 =
15 - 15 = 0