=b(a+c)(a-c)-c(a+b)(a-b)-a(b+c)(b-c)
=a^2(b-c)+b^2(c-a)+c^2(a-b)
=(b-c)*a^2 - (b^2-c^2)*a + bc(b-c)
=(b-c)*a^2 -(b+c)(b-c)*a+ bc(b-c)
=(b-c)*a^2-(b+c)*a+ bc

CPUが火を噴きそうです