Question 101869
{{{4n^2/(2n+3) - 9/(2n+3)}}}
This is not an equation. So we don't solve for n.
{{{(4n^2 - 9)/(2n+3)}}} LCD=2n+3
{{{(2n-3)cross(2n+3)/cross(2n+3)}}} Factor.  
=2n-3 Ans.
Ed