áp dụng bđt bunhiacopxki ta có \frac{25a}{b+c}+25+\frac{16b}{a+c}+16+\frac{c}{a+b}+1=(a+b+c)(\frac{25}{b+c}+\frac{16}{a+c}+\frac{1}{a+b})=\frac{1}{2}(b+c+a+c+a+b)(\frac{25}{b+c}+\frac{16}{a+c}+\frac{1}{a+b})\geq \frac{(5+4+1)^{2}}{2}=50\Rightarrow \frac{25a}{b+c}+\frac{16b}{a+c}+\frac{c}{a+b}\geq8 ta thấy dấu "=" k xảy ra \Rightarrow đpcm
áp dụng bđt bunhiacopxki ta có
\frac{25a}{b+c}+25+\frac{16b}{a+c}+16+\frac{c}{a+b}+1=(a+b+c)(\frac{25}{b+c}+\frac{16}{a+c}+\frac{1}{a+b})=\frac{1}{2}(b+c+a+c+a+b)(\frac{25}{b+c}+\frac{16}{a+c}+\frac{1}{a+b})\geq \frac{(5+4+1)^{2}}{2}=50$\Rightarrow \frac{25a}{b+c}+
\frac{16b}{a+c}+
\frac{c}{a+b}
\geq
8
ta thấy dấu "=" k xảy ra \Rightarrow$ đpcm