Click on "add vertical line off" to add discontinuity lines. Then click on "add segment" button to add functions between the lines. Note 1 - Make sure you place only one vertical line at places that require a vertical line. If you inadvertently place two vertical lines at the same place, it will appear correct visually because the lines overlap, but the system will mark it wrong. Note 2 - You should not draw an "extra" discontinuity line at the point where the curve passes the x-axis. Note 3 - Be sure to indicate the correct types of the functions between the lines, e. g. if in your answer the type of a function is "linear increasing slope" for the function that actually has linear decreasing slope, the answer will be graded as incorrect. Use the button "change segment" if necessary.