For 6x<>5y,
(24x^2-2xy-15y^2)/6x-5y=?
24x2 - 2xy - 15y2 = (6x - 5y)(4x + 3y)
(24x2 - 2xy - 15y2) / (6x - 5y) = (6x - 5y)(4x + 3y) / (6x - 5y) = 4x + 3y