How the hell do you derive an equation from a graph?
For example this inverted parabola has x-intercepts at 0 and 2, but does that really mean that the equation is -x(x-2)?
Well it cant be, because the vertex is at (1,2), and -1(1-2)=1, not 2. How do you derive equations from graphs??
You meant "does that mean the equation is y= -x(x-2)?"
And the answer is "no". It means the equation is y= ax(x-2) where a is some negative number. You can use the fact that when x= 1, y= 2 to determine a: 2= a(1)(1- 2)= -a.