云无忧624
春芽
共回答了16个问题采纳率:93.8% 举报
(x^2-a^2)/(x^2-9a^2)+(x-2a)^2/(9a^2-x^2)+(5a^2-4ax)/(x^2-9a^2)
=(x^2-a^2)/(x^2-9a^2)-(x-2a)^2/(x^2-9a^2)+(5a^2-4ax)/(x^2-9a^2)
=[(x^2-a^2)-(x^2-4ax+4a^2)+(5a^2-4ax)]/(x^2-9a^2)
=[x^2-a^2-x^2+4ax-4a^2+5a^2-4ax]/(x^2-9a^2)
=[0]/(x^2-9a^2)
=0
求采纳
1年前
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