SOLUTION: Not sure what topic this would be, but... I have this math book 'Math to the Max 1200 questions!' So far I have encountered a couple problems with answers. Simplify the follo

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Question 490863: Not sure what topic this would be, but...
I have this math book 'Math to the Max 1200 questions!' So far I have encountered a couple problems with answers.
Simplify the following expression.
4x^-2(3ax)^5
The simplified answer I came up with is: 972a^5x^3
The simplified answer in the book is: 108a^3x
This doesn't make any sense to me. I have also checked using a few online expression calculators/simplify that came up with the same answer I have. 972a^5x^3 What is the correct answer? :( He explains the method he used to get the answer, but it doesn't make sense and he never explained it before the exercise questions.
One more :)
Simplify the following expression.
(3x)^3 / x^2*x^4 (online calcs need the last bit in parentheses, so, (x^2*x^4)
The simplified answer I came up with (and online calculators): 27/x^3
The simplified answer the author came up with: 27x/3
It doesn't make any sense... :( Unless the author is incorrect. Haha, I can hope. :D

Thanks for your time. :)

Answer by mananth(16946) (Show Source):
You can put this solution on YOUR website!

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I think you are right