x²-1分之3x+4-x-1分之2括号除以x²-2x+1分之x+2=[(3x+4)/(x²-1)-2/(x-1)]÷[(x+2)/(x²-2x+1)]=[(3x+4)/[(x-1)(x+1)]-2/(x-1)]×[(x-1)²/(x+2)]=[(3x+4)/(x+1)-2]×[(x-1)/(x+2)]=[3x+4-2(x+1)]×(x-1)/[(x+2)(x+1)]=(x+2)×(x-1)/[(x+2)(x+1)]=(x-1)/(x+1)