Ответ:
(x-380)*50=2000
x-380=2000/50
x-380=40
x=40+380
x=420
(420-380)*50=2000
40*50=2000
8x+29x+618=1543
37х+618=1543
37х=1543-618
37х=925
х=925:37
х=25