For finding the z - intercept put x = 0 and y = 0
z = - D / C NEW_LINE return [ x , y , z ] NEW_LINE def equation_plane ( p , q , r ) : NEW_LINE x1 = p [ 0 ] NEW_LINE y1 = p [ 1 ] NEW_LINE z1 = p [ 2 ] NEW_LINE x2 = q [ 0 ] NEW_LINE y2 = q [ 1 ] NEW_LINE z2 = q [ 2 ] NEW_LINE x3 = r [ 0 ] NEW_LINE y3 = r [ 1 ] NEW_LINE z3 = r [ 2 ] NEW_LINE