q3-2q-1=0咋解?
<p>问题：q3-2q-1=0咋解?<p>答案：↓↓↓<p class="nav-title mt10" style="border-top:1px solid #ccc;padding-top: 10px;">景为平的回答：<div class="content-b">网友采纳 q^3-2q-1=0,→q^3+1-2q-2=0,→(q^3+1)-2(q+1)=0,→ (q^3+1)-2(q+1)=0,→(q+1)(q^2-q+1))-2(q+1)=0,→ (q+1)(q^2-q-1))=0,→ (q+1)=0或(q^2-q-1))=0,→ 1.(q+1)=0,→q=-1 2.q^2-q-1=0,→(用求根公式)q=(1±√5)/2 ∴q3-2q-1=0有三个根: -1,(1+√5)/2,(1-√5)/2
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