Х + 1075 = 3806
х=3806 - 1075
х = 2731
===============
2731 +1075 = 3806
3806=3806
3000 + х = 9000
х = 9000 - 3000
х = 6000
=============
3000 + 6000 = 9000
9000 = 9000
х - 287 =593
х = 593 + 287
х = 880
=============
880 - 287 = 593
593=593
х : 5 =80
х = 80 * 5
х = 400
=============
400 : 5 = 80
80=80
х + 1540 = 12320
х = 12320 - 1540
х =10780
===============
10780 + 1540 = 12320
12320 = 12320
8000 : х = 400
х = 8000:400
х = 20
===========
8000 : 20 = 400
400 = 400