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