SOLUTION: How do i solve this problem? 1/5r^2-2=5/6 The book says its 510/6, but i keep getting 85/6. What am I doing wrong?

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons -> SOLUTION: How do i solve this problem? 1/5r^2-2=5/6 The book says its 510/6, but i keep getting 85/6. What am I doing wrong?      Log On


   

Question 576318: How do i solve this problem? 1/5r^2-2=5/6
The book says its 510/6, but i keep getting 85/6. What am I doing wrong?
Answer by vleith(2983) About Me  (Show Source):
You can put this solution on YOUR website!
You are almost there. You are probably getting
6r%5E2+=+85
r%5E2+=+85%2F6
r+=+sqrt%2885%2F6%29
But your answer needs to be rationalized (it should not have a square root in its denominator
r+=+sqrt%2885%2F6%29+%2A+sqrt%286%2F6%29
r+=+sqrt%28510%29+%2F+6+