wbs814
幼苗
共回答了16个问题采纳率:81.3% 举报
[(ab-bc)^2-(ab+bc)^2+2(ab+bc)(ab-bc)]/2b^2
=[(ab-bc)²-(ab+bc)²+2(ab+bc)(ab-bc)]/2b²
=[(ab-bc)²+(ab+bc)²-2(ab+bc)²+2(ab+bc)(ab-bc)]/2b²
=[【(ab-bc)+(ab+bc)】²-2(ab+bc)²]/2b²
=[【2ab】²-2b²(a+c)²]/2b²
=a²-(a+c)²
=a²-a²-2ac-c²
=-c(2a+c)
1年前
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