(a+b+c)^2=a^2+b^2+c^2 +2ab+2bc+2ac=36=>ab+bc+ca=(36-14)/2=11(a+b+c)^3=a^3+b^3+c^3+3a^2b+3a^2c+3ab^2+3ac^2+3b^c+3bc^2+6abc=3(a^2+b^2+c^2)(a+b+c)-2(a^3+b^3+c^3)+6abc=216=>abc=6所以1/a+1/b+1/c=ab+bc+ca/abc=11/6
