Răspuns: a = 625
Explicație pas cu pas:
5 × 8 : [( a : 25 + 5 ) : 6 + 3 × 5] = 2
40 : [( a : 25 + 5 ) : 6 + 15] = 2
( a : 25 + 5 ) : 6 + 15 = 40 : 2
( a : 25 + 5 ) : 6 + 15 = 20
( a : 25 + 5 ) : 6 = 20 - 15
( a : 25 + 5 ) : 6 = 5
a : 25 + 5 = 5 × 6
a : 25 + 5 = 30
a : 25 = 30 - 5
a : 25 = 25
a = 25 × 25
a = 625
_____________________________________________
25 × 25 = 25 × ( 20 + 5 ) = 25 × 20 + 25 × 5 = 500 + 125 = 625