(1)
原式=(x²-4y²) +(2x-4y)
=(x+2y)(x-2y)+2(x-2y)
=(x-2y)(x+2y+2)
(2)
原式=14(x-y)-7(x-y)²
=7(x-y) [2-(x-y)]
=7(x-y)(2-x+y)