Integrated Math 1
posted by Tifini on .
What is the coefficient of the xy^2 term in the expansion of (3x + y)^3? Use the binomial theorem.

In this case it is just as easy to simply expand it
= (3x)^3 + 3(3x)^2 y + 3(3x)(y^2) + y^3
so we want the second last term which is
9xy^2