Решить уравнение 3986-(570+а)*6+281 = 673

3986-(570+а)*6+281=673
3986-(570+а)*6=673-281
3986-(570+а)*6=392
(570+а)*6=3986-392
(570+а)*6=3594
570+а=3594:6
570+а=599
а=599-570
а=29
673=673