meili 发表于 2022-10-27 16:12:17

设A=5x2+4x-1,B=-x2-3x+3,C=8-7x-6x2,请说明A-B+C的值与x的取值无关.

<p>问题:设A=5x2+4x-1,B=-x2-3x+3,C=8-7x-6x2,请说明A-B+C的值与x的取值无关.
<p>答案:↓↓↓<p class="nav-title mt10" style="border-top:1px solid #ccc;padding-top: 10px;">丁原的回答:<div class="content-b">网友采纳  A-B+C=(5x2+4x-1)-(-x2-3x+3)+(8-7x-6x2)  =5x2+4x-1+x2+3x-3+8-7x-6x2  =4,  ∵4是常数,不含x的式子,  ∴A-B+C的值与x的取值无关.
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