Răspuns:
{[(27×a-79)×61-78]×15+340}:250=4
[(27×a-79)×61-78]×15+340 = 4 x 250
[(27×a-79)×61-78]×15+340 = 1000
[(27×a-79)×61-78]×15 = 1000-340
[(27×a-79)×61-78]×15 = 660
(27×a-79)×61-78 = 660:15
(27×a-79)×61-78 = 44
(27×a-79)×61 = 44+78
(27×a-79)×61 = 122
27×a-79 = 122:61
27×a-79 = 2
27xa = 2+79
27xa = 81
a = 81:27
a = 3
