Hi all!

My math problem is about a Finance class, but it is really the math that gets me into trouble. Please see the equation:

(15/(1+r))+(10/(1+r)^2)+(8/(1+r)^3)-25=(2.5/(1+r))+(2.5/(1+r)^2)+(2.5/(1+r)^3)

I guess the first step would be to get it all to one side of the equation. In particular, I am wondering what to do with the denominators. Can I add them up?

Please note I'm only allowed to use a basic (i.e. non-graphic) calculator.

Thank you!

Sebastiaan