Răspuns:
6 + [ 15 - ( 8 : a × 7 + 7 )] × 5 = 11
6 + [ 15 - ( 8/x × 7 + 7 )] × 5 = 11
6 + [ 15 - ( 56/x + 7 )] × 5 = 11
6 + ( 15 - 56/x - 7 ) × 5 = 11
6 + ( 8 - 56/x ) × 5 = 11
6 + 8 × 5 - 5 × 56/x = 11
6 + 40 - 280/x = 11
46 - 280/x = 11
-280/x = 11 - 46
-280/x = -35
280 = 35x
x = 280 : 35
x = 8
