https://zh.frojeostern.com/post/it-is-known-that-there-is-a-point-a-on-the-coordinate-plane-whose-coordinate-is-1-2-if-there-is-a-point-b-in-the-second-quadrant-and-the-distance-from-point-b-to-the-x-axis-is-equal-to-the-distance-from-point-a-to-the-x-axis-what-is-the-equation-of-the-straight-line-ab-98-basic-measurement