（1）2x²-32
=2(x²-16)
=2(x+4)(x-4)
（2）（x-1）²-9
=[(x-1)+3][(x-1)-3]
=(x+2)(x-4)
（3）a的五次方-a
=a(a的4次方-1)
=a(a²+1)(a²-1)
=a(a²+1)(a+1)(a-1)
（4）16x²-9y²
=(4x)²-(3y)²
=(4x+3y)(4x-3y)·16x的四次方-81y的四次方·（x-y）²-4（x+y）²就這兩道題了，=(4x²)²-(9y²)²=(4x²+9y²)(4x²-9y²)=(4x²+9y²)(2x+3y)(2x-3y) =(x-y)²-[2(x+y)]²=(x-y+2x+2y)(x-y-2x-2y)=(3x+y)(-x-3y)=-(3x+y)(x+3y)