(11/х)-5/(х+18)=0 х≠0 х≠-18
11х+198-5х=0
6х=-198
х=-33
прих=0 и х=-18 не имеет смысла
(X+1)^2 = X^2 + 2×X×1 + 1^2 = X^2 + 2X + 1
3^(x+1)+2*3*3^(x+1)=21; 3^x+1(1+2*3)=21; 3^(x+1)*7=21; 3^(x+1)=3; x+1=1; x=1-1; x=0.
...............................................................не удаляй..............................................................