lim (3x^2-2x-1)/(2x^2-3x+1)
=lim (3x+1)(x-1) / (2x-1)(x-1)
=lim (3x+1)/(2x-1)
上下同时除以x
=lim (3+1/x)/(2-1/x)
=(3+0)/(2-0)
=3/2
有不懂欢迎追问