17х-8х+52=2815 15*(2х+11)=285 7*(123-4х)=794
17х-8х+52=2815 9х=2815-52 9х=2763 х=2763:9 х=307 15(2х+11)=285 30х+165=285 30х=285-165 30х=120 х=120:30 х=4