1）(a^2-1)/(-a)·(2ab^2)/(a^2-2a+1)
=(a+1)(a-1)·(-2b^2)/(a-1)^2
=-2b^2(a+1)/(a-1)

2）(x^2-3x)/(x+2)÷(x-3)/(x^2-4)
=x(x-3)/(x+2)*(x+2)(x-2)/(x-3)
=x(x-2)
=x^2-2x