1,Cho a,b,c >0 abc=1 .CMR
\frac{3a+b}{a^{2}+1}+\frac{3b+4}{b^{2}+1}+\frac{3c+4}{c^{2}+1}\leq \frac{21}{2}
2,Cho a,b,c là 3 cạnh của tam giác.CMR
a)\frac{a(b+c)}{a^{2}+2bc}+\frac{b(c+a)}{b^{2}+2ca}+\frac{c(a+b)}{c^{2}+2ab}\leq 2
b)
$\frac{5a+3b}{3a+b+2c}+\frac{5b+2c}{3b+c+2a}+\frac{5c+3a}{3c+a+2b}\geq 4$