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\({f(5x)}*{f(\frac{x}{5})}={f(5)}*{f(\frac{1}{5})}=125^2\) and since \(f(x) = f(1)=125\), then \({f(5x)}*{f(\frac{x}{5})}=125^2=(f(x))^2\).

Answer: A.

Hope it's clear.

Can we take constant 5 outside of f(5x) i.e 5f(x) ? I was able to arrive at the answer by taking constant outside of the function,but not sure whether it is correct approach or not.

In step 3, you have multiplied 1. & 2. What would be the answer if you divide 1. by 2. ? I am kinda confused. I get f(5x)/f(x/5) = 1/5^6. Help, thanks!

In step 3, you have multiplied 1. & 2. What would be the answer if you divide 1. by 2. ? I am kinda confused. I get f(5x)/f(x/5) = 1/5^6. Help, thanks!

The questions is "what is the value of \(f(5x)*f(\frac{x}{5})\)..." (f(5x) multiplied by f(x/5)) not "what is the value of \(\frac{f(5x)}{f(\frac{x}{5})}\)..." (f(5x) divided by f(x/5)). _________________

Re: If f(x)=125/x^3, what is the value of f(5x)*f(x/5) in terms [#permalink]
18 Jul 2013, 21:47

Bunuel wrote:

mneeti wrote:

The questions is "what is the value of \(f(5x)*f(\frac{x}{5})\)..." (f(5x) multiplied by f(x/5)) not "what is the value of \(\frac{f(5x)}{f(\frac{x}{5})}\)..." (f(5x) divided by f(x/5)).

Please refer your Ist response in this topic, the quoted part asks to find \(\frac{f(5x)}{f(\frac{x}{5})}\). Also, the question I have from my source of practice questions requires to find the \(\frac{f(5x)}{f(\frac{x}{5})}\). Thanks!

Re: If f(x)=125/x^3, what is the value of f(5x)*f(x/5) in terms [#permalink]
18 Jul 2013, 21:49

Expert's post

mneeti wrote:

Bunuel wrote:

mneeti wrote:

The questions is "what is the value of \(f(5x)*f(\frac{x}{5})\)..." (f(5x) multiplied by f(x/5)) not "what is the value of \(\frac{f(5x)}{f(\frac{x}{5})}\)..." (f(5x) divided by f(x/5)).

Please refer your Ist response in this topic, the quoted part asks to find \(\frac{f(5x)}{f(\frac{x}{5})}\). Also, the question I have from my source of practice questions requires to find the \(\frac{f(5x)}{f(\frac{x}{5})}\). Thanks!

Please refer to the same post: in order the answer to be A, the question should read: If \(f(x) = \frac{125}{x^{3}}\), what is the value of \(f(5x)*f(\frac{x}{5})\) in terms of f(x)? _________________

\({f(5x)}*{f(\frac{x}{5})}={f(5)}*{f(\frac{1}{5})}=125^2\) and since \(f(x) = f(1)=125\), then \({f(5x)}*{f(\frac{x}{5})}=125^2=(f(x))^2\).

Answer: A.

Hope it's clear.

Can we take constant 5 outside of f(5x) i.e 5f(x) ? I was able to arrive at the answer by taking constant outside of the function,but not sure whether it is correct approach or not.

It depends on HOW are you doing that. Please show your work. _________________

Re: If f(x)=125/x^3, what is the value of f(5x)*f(x/5) in terms [#permalink]
30 Aug 2014, 07:13

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