Ideas There are two formulas: 1. Know the coordinates of two points (x1, y1,), (x2, y2). Find the linear equation (general form) A x + B y + C = 0 Ax+By+C=0Ax+By+C=0 A = y 2 - y 1, B = x 1 - x 2, C = x 2 ∗ y 1 - x 1 ∗ y 2 A = y2-y1, B = x1-x2, C = x2 * y1-x1 * y2A=y 2−y1,B=x1−x2,C=x2∗y1−x1∗y 2 2. Known two straight line equations (general form) A 1 x + B 1 y + C 1 = 0 A_1x+B_1y+C_1=0A1x+B1Y+C1=0 A 2 x + B 2 y + C 2 = 0 A_2x + B_2y + C_2 = 0A2x+B2Y+C2=0 Find the point of intersection of two straight lines (when there is an intersection point) x = B 1 ∗ C 2 − B 2 ∗ C 1 A 1 ∗ B 2 − A 2 ∗ B 1 x = \frac{B_1*C_2-B_2*C_1 }{A_1*B_2-A_2*B_1}x=A1∗B2−A2∗B1B1∗C2−B2∗C1 y = A 2 ∗ C 1 − A 1 ∗ C 2 A 1 ∗ B 2 − A 2 ∗ B 1 y= \frac{A_2*C_1-A_1*C_2}{A_1*B_2-A_2*B_1} Y=A1∗B2−A2∗B1A2∗C1−A1∗C2