Question

(a+b)(b+c)(a+c)+abc; если a+b+c=0

Answer 1

а=-b-c
(-b-c+b)(b+c)(-b-c+c)+(-b-c)*bc=-c(b+c)(-b)-b^2c-c^2b=cb(b+c)-b^2c-c^2b=b^2c+bc^2-b^2c-bc^2=0