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Re: The function f is defined by f(x)=2^x-3. If f(x)=31, then the value of
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01 Jan 2017, 16:41

Top Contributor

Zoser wrote:

I have a somehow silly question, but how to know that the expression in the question is:

2^x-3 (where 3 is not part of the exponent) and not x^(2-3) where 3 is part of the exponent?

Good question. It's tough to avoid ambiguity in these forums. Brackets would certainly help. The prompt could have been written as: f(x)=(2^x) - 3 Alternatively, if the 3 were part of the exponent, we could have written: f(x) = 2^(x-3)

On the official GMAT, you won't have to worry about that, since the exponents will be raised.

Re: The function f is defined by f(x)=2^x-3. If f(x)=31, then the value of
[#permalink]

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02 Jan 2017, 06:48

GMATPrepNow wrote:

Zoser wrote:

I have a somehow silly question, but how to know that the expression in the question is:

2^x-3 (where 3 is not part of the exponent) and not x^(2-3) where 3 is part of the exponent?

Good question. It's tough to avoid ambiguity in these forums. Brackets would certainly help. The prompt could have been written as: f(x)=(2^x) - 3 Alternatively, if the 3 were part of the exponent, we could have written: f(x) = 2^(x-3)

On the official GMAT, you won't have to worry about that, since the exponents will be raised.

Cheers, Brent

Yes you are right. And sometime it led me to a very different answer.