Choa, b, c là độ dài 3 cạnh 1 tam giác. CMR:
1, \(abc\ge\left(a+b-c\right)\left(a-b+c\right)\left(-a+b+c\right)\)
2, \(\dfrac{1}{8}\left(a+b\right)\left(b+c\right)\left(c+a\right)\ge\sqrt{abc\left(a+b-c\right)\left(a-b+c\right)\left(-a+b+c\right)}\)