how to do this on desmos and someone told me this and i dont understand( Create a table in Desmos with 3 points: (9, -14), (9 + d, 0) (9 - d, 0). Add a slider for d. Do a quadratic regression, y1~ax12 + bx1 + c. Move the slider for d around and you'll see that a + b + c will cross -12, and get very