Notez numarul cu ,,a"
( 3 × a + 7 ) : 2 - 25 = 16
( 3 × a + 7 ) : 2 = 16 + 25
( 3 × a + 7 ) : 2 = 41
3 × a + 7 = 41 × 2
3 × a + 7 = 82
3 × a = 82 - 7
3 × a = 75
a = 75 : 3
a = 25 → numarul, aflat prin metoda mersului invers
Verific:
( 3 × 25 + 7 ) : 2 - 25 = 16
= ( 75 + 7 ) : 2 - 25 =
= 82 : 2 - 25 =
= 41 - 25 =
= 16
