∵x^2-3x+2/x^2-1=﹙x-1﹚﹙x-2﹚／﹛﹙x-1﹚﹙x+1﹚﹜=﹙x-2﹚／﹙x+1﹚
x-3/x^2+x=﹙x-3﹚／﹛x﹙x+1﹚﹜
∴x^2-3x+2/x^2-1除以x-3/x^2+x
=﹛﹙x-2﹚／﹙x+1﹚﹜／[﹙x-3﹚／﹛x﹙x+1﹚﹜]
=x﹙x-2﹚／﹙x-3﹚