Question 36485
You can find the domain and range from the graph, so if you have a graphing calculator, this is one GOOD way to find domain and range-- draw the graph on your calculator.  


The alternatives to the graphing calculator would be to find the vertex by using the formula {{{y = -b/(2a) }}} or the completing the square method.  By any of these methods, this is what the graph should look like:

{{{graph (300,300,-6, 6, -20, 10, x^2-2x-15) }}}



From this graph, you can see that the graph extends from left to right from (-infinity to postiive infinity.  In interval notation this would be 

Domain = (-inf, inf).


The graph extends, as you can see from the graph, from it's lowest point at the vertex at (1,-16) upward to infinity.   That would be the 

Range = [-16, inf).


R^2 at SCC