{2*x/y+2*y/x=18 үсті
{x+y=12 асты
2*(12-y)/y+2*y/(12-y)=18
(24-2*y)/y+2*y/(12-y)=18
(((12-y)*(24-2*y))+(2*y^2))/(12*y-y^2)=18
288-24*y-24*y+2*y^2+2*y^2=18*(12*y-y^2)
4*y^2-48*y+288=216*y-18*y^2
4*y^2-48*y+288-216*y+18*y^2=0
22*y^2-264*y+288=0
D=264^2-4*22*288=44352
44352^0.5=24*77^0.5
y1=(264+(24*77^0.5))/(2*22)=6+(6*77^0.5)/11
x1=12-6+(6*77^0.5)/11=6-(6*77^0.5)/11
y2=(264-(24*77^0.5))/(2*22)=6-(6*77^0.5)/11
x2=12-6-(6*77^0.5)/11=6+(6*77^0.5)/11