Factorise the following:

3ax - 6ay - 8by + 4bx

3ax - 6ay - 8by + 4bx

= 3ax - 6ay + 4bx - 8by

Taking out common terms we get,

3ax - 6ay + 4bx - 8by

= 3a(x - 2y) + 4b(x - 2y)

= (x - 2y)(3a + 4b).

Hence, 3ax - 6ay - 8by + 4bx = (x - 2y)(3a + 4b).