first, f(x)=x(x-4)=x²-4x using algebra completeing the square (x²-4x+4)-4 (x-2)²-4 f(x)=(x-2)²-4
the vertex is at (2,-4) and the axis of symmetry is x=2 that means that x=2 is the mirror line that means any point that is d units from the axis of symmetry in a horizontal direction will also have a mirror point on the other side of x=2 sorry if confusing, but explanation is axis of symmetry is at x=2
