Question 1044858
recall:

All the values that go {{{into}}} a function are  called the  {{{domain}}}.
The {{{output}}} values are called the {{{range}}}.
Now, what comes out (the Range) depends on what we put in (the Domain).
{{{Domain }}}→ {{{Function}}} → {{{Range}}}

 the domain of the function {{{f(x)= (x^2-16)/7}}} is {{{R}}} (all real numbers); no matter what value you take for {{{x}}} you will always get value for {{{f(x)}}}, means function is defined


one more example if we have {{{x}}} in denominator: 
The domain of {{{f(x)=1/x}}} is all the Real Numbers {{{R}}}, except {{{0}}} 

{{{1/x}}} is {{{undefined}}} at {{{x=0}}} because {{{1/0}}} would be dividing by zero