I help some help please.
Basically if i had a graph of e.g.
I know that my graph would intersect the x-axis at x=2 and x=4.
However if I didn't know the equation of my curve, but knew the shape of the graph was like y=-(x-3)^2+1, and it crossed the x-axis at 2 points.
How could I prove that it had 2 roots?
I think I may have something to do with continuity, but not sure.
Any help is appreciated.