SOLUTION: I need help finding the domain for the following problem: f(x)= {{{x^2-9}}} / {{{x^2-10x+21}}} I hope that I've input the problem correctly. Thanks, Frank

Algebra ->  Functions -> SOLUTION: I need help finding the domain for the following problem: f(x)= {{{x^2-9}}} / {{{x^2-10x+21}}} I hope that I've input the problem correctly. Thanks, Frank      Log On


   



Question 379445: I need help finding the domain for the following problem:
f(x)= x%5E2-9 / x%5E2-10x%2B21
I hope that I've input the problem correctly.
Thanks,
Frank

Answer by fractalier(6550) About Me  (Show Source):
You can put this solution on YOUR website!
The domain of a function are all allowable values for x.
The only values of x that WOULDN'T be allowed here are those which make the denominator go to zero...so we set it equal to zero and solve it...
So
x%5E2+-+10x+%2B+21+=+0
%28x+-+7%29%28x+-+3%29+=+0
x+=+7+or+x+=+3
Thus the domain is all real numbers except x cannot be 3 or 7.