原式化简：{（x-3)(x-2)/(x-3)(x-4)}²÷{(x+1)(x+2)/(x-4)(x+2)}²
{(x-2)/(x-4)}²÷{(x+1)/(x-4)}²
{(x-2)/(x-4)×(x-4)/(x+1)}²
{(x-2)/(x+1)}²
把x=-2代入得16