2 2 (a + b - c) *(a - b + c)
(a + b - c)^2*(a - b + c)^2
(a + b - c)^2*(a + c - b)^2
4 4 4 3 3 2 2 2 2 2 2 2 a + b + c - 4*b*c - 4*c*b - 2*a *b - 2*a *c + 6*b *c + 4*b*c*a
a^4 + b^4 + c^4 - 4*b*c^3 - 4*c*b^3 - 2*a^2*b^2 - 2*a^2*c^2 + 6*b^2*c^2 + 4*b*c*a^2