Question

whats the domain of y=x^2-9

Answer 1

@ganeshie8

Answer 2

So the key here is, what is domain and what is range?

Domain is all the possible values you can plug into your equation.
Range is all the possible values you can get from plugging all the values from your domain into the equation.

So we're just looking at domain right now, can you think of a single number that we can't plug into x^2-9 by replacing x? It doesn't seem like there is to me, so all real numbers is your domain.

What might stop us from plugging something in? Well, what if we had 1/x ? You can't divide by zero, so 0 is not in the domain, we have to remove it. Also, you can't take the square root of negative numbers, so we gotta pull those out as well if you encounter that.