First, we find the least common denominator. We have to make 3n^2 and 2n the same. How?
I multiply 3n^2 by 2.
I multiply 2n by 3n.
Let's do it now.
Given: $\displaystyle \frac{2}{3n^2} + \frac{5}{2n}$
Use 2 and 3n to multiply by 1: $\displaystyle \frac{2}{3n^2} \cdot \frac{2}{2} + \frac{5}{2n} \cdot \frac{3n}{3n}$
$\displaystyle \frac{4}{6n^2} + \frac{15n}{6n^2} = \frac{4+15n}{6n^2}$