﹙x²-4x-21﹚÷﹙x﹢3﹚

问题描述:

﹙x²-4x-21﹚÷﹙x﹢3﹚

﹙x²-4x-21﹚÷﹙x﹢3﹚
=﹙x-7﹚﹙x+3﹚÷﹙x﹢3﹚
=X-7