12/х-3 + 5/х+3 - 18/х = 0
12х*(х+3)+5х*(х-3)-18(х-3)*(х+3)/х*(х-3)*(х+3)=0
12х²+36х+5х²-15х-18(х²-9)/х*(х-3)*(х+3)=0
12х²+36х+5х²-15х-18х²+162/х*(х-3)*(х+3)=0
-х²+21х+162/х*(х-3)*(х+3)
-х²+21х+162=0
х²-21х-162=0
Д=в²-4*а*с=-21²-4*1*(-162)=1089
х=21±33/2
х=21+33/2=27
х=21-33/2=-6
х=27
х=-6
Ответ х1= -6 ,х2 = 27