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 Question from ellen, a student: 7/ab to the -4 power

Hi Ellen,

You didn't give instructions but I assume you are to "simplify" or "write without the negative exponent". You have

$\frac{7}{a b^{-4}}.$

First of all focus on the denominator alone to get

$a b^{-4} = a \times \frac{1}{b^4} = \frac{a}{b^4}.$

The original expression then can be written as

$\frac{7}{\frac{a}{b^4}} = 7 \times \frac{b^4}{a} = \frac{7 b^4}{a}$

I hope this helps,

Penny

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