The general equation $ax^2$ + 2hxy + $by^2$ + 2gx + 2fy + c = 0 represents a pair of straight lines when Delta = abc + 2fgh - $af^2$ - $bg^2$ - $ch^2$ = 0. Here the coefficients follow the notation: a ($x^2$), 2h (xy), b ($y^2$), 2g (x), 2f (y), c (constant). The point of intersection is found by solving the partial derivatives: ax + hy + g = 0 and hx + by + f = 0. The angle between the lines is the same as the homogeneous case: tan(theta) = 2sqrt($h^2$ - ab)/|a + b|. The lines are parallel when $h^2$ = ab and the Delta condition still holds (giving two parallel lines). The distance between parallel lines represented by this equation is 2sqrt$\frac{g^2 - ac}{sqrt}$(a(a + b)).