Răspuns:
( a × 8 + 24 ) : 8 - 3 + 7 = 12
( a × 8 + 24 ) : 8 - 3 = 12 - 7
( a × 8 + 24 ) : 8 - 3 = 5
( a × 8 + 24 ) : 8 = 5 + 3
( a × 8 + 24 ) : 8 = 8
a × 8 + 24 = 8 × 8
a × 8 + 24 = 64
a × 8 = 64 - 24
a × 8 = 40
a = 40 : 8
a = 5
6 × 8 - a + 25 : 5 = 50
48 - a + 5 = 50
48 - a = 50 - 5
48 - a = 45
a = 48 - 45
a = 3