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(A) 2^4x
(B) ...
(C) ...
(D) ...
(E) ...

*This question is included in Nova Math - Diagnostic/Review:

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Stacy Dam

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Posted: 07/11/2012 16:28

Can someone help me on this?

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Admin

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Posted: 07/18/2012 22:25

Hi Stacy. When an exponent is raised to another power, you simply multiply the "powers". In this case, 4 is raised to the power of x, then raised again to the power of 2. You simply multiply x by 2. So, we have 4^2x. But we don't have that as a choice. However, we know that 4 is 2^2 (2 squared, or 2 raised to the power of 2), so we can write the expression as (2^2)^2x.

So, again we can multiply the powers, making it: 2 raised to the power of 2⋄2x, or 2^4x, which is choice A.

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Nye Ree

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Posted: 08/17/2016 12:22

I don't understand why the square doesn't apply to the coefficient as well. I came to the answer 16^(2x) or even 2^(8x)

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Admin

Reply 1 of 1
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Posted: 08/17/2016 14:41

Hi Nye,

We can use only the existing rules for manipulating exponents. You are tacitly using the rule (ab)^n = (a^n)(b^n).

But the x in the problem is not in the same position as the b in this rule, so this rule cannot be used. That is, we do not have the following:

(4x)^2 = (4^2)(x^2) = 16x^2

Nova Press

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