Question 92834
You can't solve it (no = sign), just simplify it. 
:

{{{4r^2-25s^2}}}
------------------
{{{2r^2+3rs-20s^2}}}
:
Both the numerator & denominator can be factored:
{{{(2r-5s)(2r+5s)}}}
------------------
{{{(2r-5s)(r+4s)}}}
:
Note that (2r-5s)'s will cancel, leaving you with:
{{{(2r+5s)}}}
-----------
{{{(r+4s)}}}
:
Did this make sense to you?