915..............................
3х+9х+352=5260 17(2х-15)+82=3193 21х-5х-84=940 12х+352=5260 34х-255+82=3193 16х-84=940 12х=5260-352 34х-173=3193 16х=940+84 12х=4908 34х=3193+173 16х=1024 х=4908:12 34х=3366 х=1024:16 х=409 х=3366:34 х=64 х=99
(3х+41)*28-248=3000
ответ х=25