160 140 120 Area 100 (m) 80 60 40 8832 20 5 10 15 20 20 Length of a Side (m) The axis of symmetry is the vertical line that goes through the vertex. The equation for a vertical line is in the form x = a, where a is the x value the line passes through. For the graph above, the axis of symmetry is x = The x-intercepts are where the function crosses (or touches) the x-axis. What are the x- intercepts for this function? Enter them as ordered pairs. ) and ( The domain is the set of all possible input values (x). For quadratic functions, the domain will be all real numbers. This can be shown as -00