Expert: Sherry Wallin - 12/8/2008

Question
f(x)=4/(x^9-256x)

Answer
Hi Junaid~
    I am going to assume you are looking for the domain of the function you gave. The domain is all possible values your x can take on without violating basic principles. The most common places in beginning or intermediate algebra would be when you study rational expressions or when you are finding the square roots of a function. So just remember you can not divide by zero and you can not take the square root of a negative number when you are looking for a solution in the real numbers.
So in your problem, all you have to do is factor the denominator and find the values of x that would make the denominator equal to 0.
X^9-256x = 0 then x^8(x-256) = 0, so either x = 0 or x-256 = 0 which means x = 256 makes the denominator 0 also. So x can be anything real number EXCEPT 0, 256

Math Prof