#1**+1 **

Let's do it this way.....let x= n^2

Substitute:

x^2 -11x+30 / x^2-7x+10 factor top and bottom

(x-6)(x-5) / (x-2)(x-5) Now put the n's back in

(n^-6)(n^2-5) / (n^2-2)(n^2-5) Now you can see that n^2 cannot equal 2 or 5

so n cannot equal +-sqrt2 or +- sqrt 5

cancel out the (n^2-5) in num and denom

(n^2-6) / (n^2-2)

ElectricPavlov
Feb 28, 2018