OK, for this problem, we're going to find F of -7. So we're going to stick -7 in. Every time we see our X doing some plug and chug, we get -2029 when we look at F of -1, we put -1 and every time we see our X and we get 11. So these are really, really points. When X is -7, the point -2029 comes out. When X is -1, the point 11 comes out. So if we thought about looking at a graph, if -1 produces +11 and -7 is -2029. So somewhere way way down there, it's a polynomial, IE is going to be a smooth and continuous graph. If it's continuous, does that mean that somewhere in between these two values we have to cross the X axis? The answer is yes. Now, it doesn't tell us whether we only cross once. It may be that we cross lots of times. We don't know. We are going to know that the maximum number of zeros is 3. So the one I just drew actually couldn't occur because there would have been five zeros. So we could have had one that would have gone up, down and up because that would have given us 3 zeros. Or we could have had one that just crosses one time. But we know if we have a negative Y value and a positive Y value that's somewhere between the negative Y and positive Y, we have to cross through zero.