Question

(a+b)×(a-b)×(a+3b)
Решите пожалуйста !

Answer 1

(a+b)(a-b)(a+3b)=//a+b)(a-b)/.(a+3b)=(a²-b²)(a+3b)=
=a².a +a².3b -b².a -b².3b=
=a³+3a²b-ab²-3b³