First there is a good tutorial for "LaTex" formatting that is used on this board. Just start with "[ tex ]" and end with "[/ tex ]" (without the spaces):Introducing LaTeX Math Typesetting
Please show what you have done. What did you get when you differentiated and put y, y', and y'' into the equation?
(You don't really need the "+r" in the exponent because this not really a Frobenious equation- the leading coefficient is never 0 so it is sufficient to look for a solution of the form )