Find the domain of the function. (1.4, Example 7)
f(x)=(x)/(x-9)
{x|x!=9}
, or
(-\infty ,9)\cup (9,\infty )
{x|x<0}
(-\infty ,0)
{x|x!=-9}
(-\infty ,-9)\cup (-9,\infty )
{x|x>0}
(0,\infty )
Question 3