2x/(x²-9)+1(3-x)特别是化成(x+3(x-3)之后该怎么办

分类: 作业答案 • 2021-12-19 17:22:59

问题描述：

2x/(x²-9)+1(3-x)
特别是化成(x+3(x-3)之后该怎么办

答

2x/(x²-9)+1/(3-x)
=2x/(x²-9)-1/(x-3)
=2x/(x²-9)-(x+3)/(x²-9)
=(2x-x-3)/(x²-9)
=(x-3)/【(x+3)(x-3)】
=1/(x+3)
希望采纳!