(x-83)+316=425 (600-x)-92=126 253-(x-459)=138 502-(217-x)=421 871-(x+157)=385
(х - 83) + 316 = 425
х - 83 = 425 - 316
х - 83 = 109
х = 109 + 83
- - - - - - - - - - - -
(600 - х) - 92 = 126
600 - х = 126 + 92
600 - х = 218
х = 600 - 218
253 - (х - 459) = 138
х - 459 = 253 - 138
х - 459 = 115
х = 115 + 459
502 - (217 - х) = 421
217 - х = 502 - 421
217 - х = 81
х = 217 - 81
871 - (х + 157) = 385
х + 157 = 871 - 385
х + 157 = 486
х = 486 - 157