а)(3х+5х)818=144, 8х*18=144, 8х=144:18, 8х=8, х=1. проверка: (3*1+5*1)*18=144, (3+5)*18=144, 8*18=144, 144=144. б)(7у-3у):8=17, 4у:8=17, 4у=17*8, 4у=136, у= 136:4,у=34. проверка: (7*34-3*34):8=17, (238-102):8=17, 136:8=17,17=17. в)(6а+а) :13=14, 7а :13=14, 7а=14*13,7а=182, а=182:7, а=26. проверка: (6*26 +26 ):13 =14, (156+26):13=14, 182:13=14, 14=14. г) 48:(9b-b)=2, 48: 8b=2, 8b=48:2, 8b=24, b= 24 :8, b=3. проверка: 48:(9*3-3)=2, 48:(27-3)=2, 48:24=2, 2=2.