Factorise :
(i) 15(5x−4)2−10(5x−4)(ii) 3a2x−bx+3a2−b(iii) b(c−d)2+a(d−c)+3(c−d)(iv) ax2+b2y−ab2−x2y(v) 1−3x−3y−4(x+y)2