Question 1122533
Greenestamps beat me to it.

<pre>
3. What is the value of X for which the expression is not defined: 2x^""+3/x^2-16?

I'm always suspicious when I see an expression like this with no parentheses.

If you mean what you wrote, which I doubt (from experience with students)

{{{2x+3^""/x^2-16}}} is undefined when x = 0.

If you meant this 

{{{(2x+3^"")/x^2-16}}} is undefined when x = 0.

If you meant this:

{{{2x+3^""/(x^2-16)}}} is undefined when {{{x^2-16=0}}}

That is, when {{{(x-4)(x+4)=0}}}}, or x = 4 or x = -4.

{{{(2x+3^"")/(x^2-16)}}} is undefined when {{{x^2-16=0}}}

That is, when {{{(x-4)(x+4)=0}}}, or x = 4 or x = -4.

When you type math all on one line, you must always put parentheses
around numerators and denominators.  All of the above mean different 
things.

Edwin</pre>