SOLUTION: This is the last question I'll need help with for this week! Find all numbers for which the rational expression is undefined: r^3-7r/r^2-64 Thanks!

Algebra ->  Polynomials-and-rational-expressions -> SOLUTION: This is the last question I'll need help with for this week! Find all numbers for which the rational expression is undefined: r^3-7r/r^2-64 Thanks!      Log On


   

Question 466182: This is the last question I'll need help with for this week!
Find all numbers for which the rational expression is undefined:
r^3-7r/r^2-64
Thanks!
Answer by richard1234(7193) About Me  (Show Source):
You can put this solution on YOUR website!
The rational expression is undefined when the denominator is zero and the numerator is non-zero (if we get 0/0 we say the expression is indeterminate). Here, we set r^2 - 64 equal to 0, which implies r^2 = 64, r = 8 or -8. In either case, the numerator is non-zero.