Question

1-(x-y)/(x+2y)÷（x²-y²）/（x²+4xy+4y²），化简

Answer 1

原式=1-(x-y)/(x+2y)÷(x+y)(x-y)/(x+2y)²
=1-(x-y)/(x+2y)*(x+2y)²/(x+y)(x-y)
=1-(x+2y)/(x+y)
=[(x+y)-(x+2y)]/(x+y)
=-y/(x+y)

追问

http://zhidao.baidu.com/question/439075277.html?quesup2&oldq=1

Answer 2

1－﹙x－y﹚／﹙x＋2y﹚÷﹙x+y﹚﹙x－y﹚／﹙x＋2y﹚²
＝1－﹙x－y﹚／﹙x＋2y﹚×﹙x＋2y﹚²／﹙x+y﹚﹙x－y﹚
＝1－﹙x＋2y﹚／﹙x＋y﹚
＝﹙x＋y﹚／﹙x＋y﹚－﹙x＋2y﹚／﹙x＋y﹚
＝[﹙x＋y﹚－﹙x＋2y﹚]／﹙x＋y﹚
＝﹙x＋y－x－2y﹚／﹙x＋y﹚
＝﹙﹣y﹚／x＋y