How do you find out your vocal range?

How to find domain and range of this equation?

• school just started and i completely forgot how to find the domain and range. the equation is y=x^2-2x-15 I got my graph drawn but how do I find the domain and range? thanks.

• Answer:

  So domain is which values of x still make the function true while range is the same for y values. from your graph, you are able to see that any value of x will result in an answer. Your graph continues in both ways towards infinity. Thus the domain is all real numbers similarly, the graph also shows you what the y values can be. However, the lowest possible y value is -15 (the y intercept in this case), and there are no values for x which wiill satisy a y of less than -15. If you don't believe me, try solving for -20=x^2-2x-15. But ill save you some time and tell you its impossible (unless you start getting into imaginary numbers, which im assuming you're not) :P thus the range is going to be when y is greater than or equal to -15 Hope that refreshed your memory! :)