SOLUTION: Determine the domain of {{{f(a) = (a^2-16)/( a^2-3a-28)}}} So that is f(a) = a squared - 16 divided by a squared - 3a - 28 Please help!! Thanks!

Algebra ->  Equations -> SOLUTION: Determine the domain of {{{f(a) = (a^2-16)/( a^2-3a-28)}}} So that is f(a) = a squared - 16 divided by a squared - 3a - 28 Please help!! Thanks!      Log On


   

Question 91948: Determine the domain of f%28a%29+=+%28a%5E2-16%29%2F%28+a%5E2-3a-28%29
So that is f(a) = a squared - 16 divided by a squared - 3a - 28
Please help!! Thanks!
Answer by mathispowerful(115) About Me  (Show Source):
You can put this solution on YOUR website!
f%28a%29+=+%28a%5E2-16%29%2F%28+a%5E2-3a-28%29
Let's simplify this expression first
f%28a%29+=+%28a%2B4%29%28a-4%29%2F%28a-7%29%28a%2B4%29
here a+4 canceled.
Now we have f%28a%29+=+%28a-4%29%2F%28a-7%29
Domain is a collection of all allowed x values.
in the above expression we have a -7 on the bottom, you know
it can not be 0, so a -7 can not be 0, that means a can not equal to 7,
the answer is a can be any real numbers except 7.
the graph of f%28a%29+=+%28a%5E2-16%29%2F+%28a%5E2-3a-28%29 can verify the answer
graph%28200%2C200%2C+-10%2C+10%2C+-10%2C+10%2C+%28x%5E2-16%29%2F%28x%5E2-3x-28%29%29