X2+y2-8y+in (y-kx+2k-2) = 0，x2-in kx+y2-8y+in y+in (2k-2) = 0， 16-32+4 in c (0，4)+in (2k-4) k=8+t/t！ = 8+2 inches /2 inches = 4+ inches/inch! When the red color passes through the point (0,4), it is a special coefficient. Enter 1 and a special slope k 1. Hooray! Y-2 = 4+in/4 (x-2) = 0, Y-4 decimal in/4x-2-4+in/2 = 0! The equator of the earth is round.