[(x+3分之x+2)-(x+2分之x+1)+(x+5分之x+4)-(x+4分之x+3)]除以[(x平方+8x+15)分之(x平方+7x+13)]

原式= [(1-1分之x+5)-(1-1分之x+4))+(1-1分之x+3)-(1-1分之x+2)]*[(x +3)(x+5)]\(x^2+7x+13) =[(1分之x+2)-(1分之x+3)+(1分之x+4)-(1分之x+5)]*)]*[(x +3)(x+5)]\(x^2+7x+13) =[(3分之(x+2)(x+5))-(1分之(x+3)(x+4))...