Okay, if you're finding limits by looking at graphs, then plug "y<sub>1</sub> = -1/(x<sup>2</sup> - 4)" into your graphing calculator, and look at the picture, and/or look at the TABLE values. (If necessary, ZOOM in or TRACE on the graph, or change the TBLSET settings to give a smaller increment for x.)
Is y going up to positive infinity, or down to negative infinity, or neither? ("The" limit depends on having the right-hand limit and the left-hand limit agreeing.)
(Note: Depending on the text, your book might just want an answer of "no limit", any time the limit isn't a finite value. You'll have to check your text and/or your class notes to determine this, though.)
Eliz.