(102×80)-Х=456×14
8160-Х=6384
Х=8160-6384
Х=1776
-----------------------
(651×20)-Х=1980-103
13020-х=1877
х=13020-1877
х=11143
-------------------------------
х-5004=3021×30
х-5004=90630
х=90630-5004
х=85626
-------------------------
(7005×7)-х=102×2
49035-х=204
х=49035-204
х=48831
----------------------------