a,b,c, sunt inves proportionale cu 5,6,10 se scrie astfel
a/(1/5)=b/(1/6)=c/(1/10)
dupa calcule simple obtinem
5a=6b=10c a=2c b=5c/3 pe care le inlocuim in ecuatie
[4c^2+c^2*25/9+c^2]/[2c*5c/3*c)=7/9
36c^2+25c^2+9c^2=7*(10*c^3/3)
70*c^2=70*c^3/3
3c^2=c^3 3c^2-c^3=0 c^2*(3-c)=0 cu solutia acceptabila c=3
rezulta a = 6 si b=5
