(15Х-22Х):19=2 85+48:(11-Х)=91 86-49:(2Х-5)=79
(15x-22x):19=2 -7x=2·19 -7x=38 x=-38/7 85+48:(11-Х)=91 48:(11-x)=91-85 48:(11-x)=6 11-x=48:6 11-x=8 x=11+8=19 86-49:(2Х-5)=79 49:(2x-5)=86-79 49:(2x-5)=7 2x-5=49:7 2x-5=7 2x=7+5 2x=12 x=12:2=6