Question

[Quang Nguyễn]

CMR 

a, (a+b)(b+c)(c+a)+4abc=c(a+b)^2+a(b+c)^2+b(c+a)^2

b, (a^3+b^3+c^3)^3=a^3+b^3+c^3+3(a+b)(b+c)(c+a)

thank!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!