Answer:
ok lets do it..
Explanation:
You simply multiply out each factor.
So you start by multiplying the a in (a+b) to each term in (a−2b).
You will get a2−2ab as the first portion of the answer.
So now you will do the same with the b in (a+b).
Then you get −2b2+ab.
Now you add a2−2ab and −2b2+ab to get a2−2b2−ab .
i hope it will work....