A
anh_em_02


b) Cho $a + b + c = 2010$ và $\dfrac{1}{a+b}+\dfrac{1}{b+c}+\dfrac{1}{c+a}= \dfrac{1}{3}$
Tính $S=\dfrac{a}{b+c}+\dfrac{b}{a+c}+\dfrac{c}{a+b}$
Tính $S=\dfrac{a}{b+c}+\dfrac{b}{a+c}+\dfrac{c}{a+b}$