求值域y=(xamp;#178;-8x+15)/(xamp;#178;-x-6)
<p>问题：求值域y=(xamp;#178;-8x+15)/(xamp;#178;-x-6)<p>答案：↓↓↓<p class="nav-title mt10" style="border-top:1px solid #ccc;padding-top: 10px;">牛瑞燕的回答：<div class="content-b">网友采纳 y=(x²-8x+15)/(x²-x-6)=(x-3)(x-5)/(x-3)(x+2)=(x-5)/(x+2)(x≠3) =1-7/(x+2)(x≠3) ∴y≠1且y≠(3-5)/(3+2)=﹣2／5 ∴值域是﹛y|y∈R且y≠1且y≠﹣2／5﹜
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