已知m^2-5m-1=0,则2m^2-5m+（1/m^2）为多少?
<p>问题：已知m^2-5m-1=0,则2m^2-5m+（1/m^2）为多少?<p>答案：↓↓↓<p class="nav-title mt10" style="border-top:1px solid #ccc;padding-top: 10px;">胡兵的回答：<div class="content-b">网友采纳 m²-5m-1=0两边除以m,m-5-1/m=0m-1/m=5且m²-5m-1=0,5m=m²-12m²-5m+1/m²=2m²-(m²-1)+1/m²=m²+1/m²+1m²+1/m²=(m-1/m)²+2×m×1/m=5²+2=27因此...
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