1.1/2x²-8ax+32a²

　　=1/2(x²-16ax+64a²)

　　=1/2(x-8a)²

　　2.x²(x²-y²)+z²(y²-x²)

　　=x²(x²-y²)-z²(x²-y²)

　　=(x²-y²)(x²-z²)

　　=(x+y)(x-y)(x+z)(x-z)

　　3.5a²b(x-y)³-30ab²(y-x)²

　　=5a²b(x-y)³-30ab²(x-y)²

　　=5ab(x-y)²[a(x-y)-6b]

　　=5ab(x-y)²(ax-ay-2b)