Question

已知a+2b=0求证a*a*a+2ab[a+b]+4*a*a*a=0

Answer 1

a*a*a+2ab[a+b]+4*b*b*b

=(a*a*a+2a*a*b)+(2ab*b+4*b*b*b)

=a*a(a+2b)+2b*b(a+2b)

=a*a*0+2b*b*0

=0