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Re: [m]8^c * [square_root]8[square_root][/m] = [m][fraction]8^a/ [#permalink]
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workout wrote:
\(8^c * \sqrt{8}\) = \(\frac{8^a}{8^b}\) then a =

A) \(b(\frac{1}{2} + c)\)

B) \(\frac{bc}{2}\)

C) \(\frac{b + c}{2}\)

D) \(2b + c\)

E) \(\frac{1}{2} + b + c\)


When you're dealing with exponent questions, it's usually helpful to get things to look as alike as possible. For this problem, remember that roots are just exponents: a square root is the same as the \(\frac{1}{2}\) power.

So first, rewrite the equation: \(8^c * 8^\frac{1}{2}\) = \(\frac{8^a}{8^b}\)

Next, let's get rid of the denominator by multiplying both sides by \(8^b\)

\(8^b*8^c*8^\frac{1}{2} = 8^a\)

Next, apply the power rules. When multiplying numbers with the same base, you can add the powers:

\(8^b*8^c*8^\frac{1}{2} = 8^{(b+c+1/2)}\)=\(8^a\)

Now, since the base is the same on both sides, just ignore it. \(b+c+\frac{1}{2}\) = a.

Answer: E
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Re: [m]8^c * [square_root]8[square_root][/m] = [m][fraction]8^a/ [#permalink]
Remember n^1/2 = square root of n

8^c * 8^1/2 = 8^a / 8^b

Isolate the exponents and solve for a:
c + 1/2 = a - b
c + b + 1/2 = a
Answer is E.
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Re: [m]8^c * [square_root]8[square_root][/m] = [m][fraction]8^a/ [#permalink]
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