we have
(a+b)(3a-b)(2a+7b)
step 1
Solve
apply distributive property
(a+b)(3a-b)=3a^2-ab-3ab-b^2=3a^2-4ab-b^2
step 2
Multiply (3a^2-4ab-b^2) by (2a+7b)
6a^3+21a^2b-8a^2b-28ab^2-2ab^2-7b^3=6a^3+13a^2b-30ab^2-7b^3
answer is
<h2>6a^3+13a^2b-30ab^2-7b^3</h2>
He used distributive property
5.394e+13 hope this helps
I think it's 9 but I could be wrong
