中三指數定律

雪散霞花

化簡下列數式~並以正指數表示答案~而a=/=0~

(2a^-2+a^-2)^3

我既答案係            ２７
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但係正確答案係　２７
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sapphire

[2a^(-2) + a^(-2)]^3
= [(2 + 1)a^(-2)]^3
= [3a^(-2)]^3
= 27a^(-6)
= 27 / a^6

The answer is correct.
It seems that you miscalculate and give out an extra 1/2. Then after the power of 3, it gives out 1/8. Try to find the error by checking each step.

[ 本帖最後由 sapphire 於 5/10/2008 06:44 PM 編輯 ]